Tag
practice
643 pieces tagged “practice”, newest first.
- Correction: Merge with a recency guard Data engineering
- An exercise on world-indicators Data quality
- What actually changed in this field in three years Analytics engineering
- The category that eats the chart Visualization
- Course note — Rows, grain, and the shape of a dataset Analytics practice
- mrr_usd: mean 447, median 88 Statistics
- What industry actually contains in saas-subscriptions Data quality
- The overall average hides 10 different numbers Analytics practice
- What 3,500 job postings say about salary_min_usd Analytics practice
- Correction: Counting your tests Experimentation
- An exercise on movie-ratings Data quality
- Reader question — The patterns that keep coming up Analytics engineering
- world-indicators.country: 30 values, 10.0% in the top three Visualization
- Reading country before trusting it in data-job-postings Data quality
- sessions: mean 3, median 2 Statistics
- The overall average hides 8 different numbers Analytics practice
- What 3,500 job postings say about city Analytics practice
- Correction: As-of feature computation Machine learning
- Why there is no analytics on this site Data platform
- SaaS subscriptions, in one paragraph Data quality
- Cutting a lesson down — Designing an experiment that can succeed Experimentation
- The category that eats the chart Visualization
- The average distance km is not the typical one Statistics
- Reading reopened before trusting it in support-tickets Data quality
- gdp_per_capita_usd by region: a 105% spread Analytics practice
- Correction: Fan-out join Analytics engineering
- Grid energy load, in one paragraph Data quality
- Cutting a lesson down — The first hour with an unfamiliar dataset Data quality
- saas-subscriptions.plan: 4 values, 94.0% in the top three Visualization
- What wind_mw actually contains in grid-energy-load Data quality
- The average tip usd is not the typical one Statistics
- revenue_usd by variant: a 48% spread Analytics practice
- Correction: Gaps and islands Analytics engineering
- When should I not build a model? Machine learning
- If we had to cut the course to ten lessons Experimentation
- Data job postings, in one paragraph Data quality
- Reader question — Reading a result without fooling yourself Experimentation
- flight-delays.dest: 14 values, 22.3% in the top three Visualization
- What device actually contains in ab-test-checkout Data quality
- arr_delay_min: mean 7, median 2 Statistics
- dep_delay_min by carrier: a 85% spread Analytics practice
- Correction: Idempotent window replace Data engineering
- How do I explain a confidence interval to a stakeholder? Statistics
- What is deliberately wrong with city-air-quality Data quality
- Five minutes with distance_mi in flight-delays Data quality
- Reader question — Turning a request into a question Analytics practice
- dep_delay_min by origin: a 113% spread Analytics practice
- ab-test-checkout.variant: 3 values, 100.0% in the top three Visualization
- Somebody translated the course into Portuguese Analytics practice
- first_response_min: mean 155, median 83 Statistics
- Correction: Deterministic surrogate key Data engineering
- Content is files, not a database Data platform
- What is deliberately wrong with flight-delays Data quality
- Course note — Colour is an encoding, not decoration Visualization
- The category that eats the chart Visualization
- fare_usd: mean 22.16, median 14.29 Statistics
- Five minutes with year in world-indicators Data quality
- The overall average hides 4 different numbers Analytics practice
- One question I ask in every code review Analytics engineering
- Correction: Contract check at the boundary Data quality
- What "free" means here, precisely Data platform
- Flight delays, in one paragraph Data quality
- Course note — The patterns that keep coming up Analytics engineering
- The category that eats the chart Visualization
- The overall average hides 6 different numbers Analytics practice
- The average sessions is not the typical one Statistics
- Five minutes with cancelled in flight-delays Data quality
- Correction: Forward-chaining split Machine learning
- What is deliberately wrong with saas-subscriptions Data quality
- retail-orders.category: 6 values, 59.5% in the top three Visualization
- Course note — A working setup that will not embarrass you Data engineering
- gdp_per_capita_usd: mean 26,959, median 20,761 Statistics
- What salary_max_usd actually contains in data-job-postings Data quality
- first_response_min by channel: a 11% spread Analytics practice
- Correction: The grain uniqueness test Data quality
- What is deliberately wrong with sensor-telemetry Data quality
- Course note — Joins that do not fan out Analytics engineering
- The category that eats the chart Visualization
- The average arr delay min is not the typical one Statistics
- Reading borough before trusting it in ride-hail-trips Data quality
- population by country: a 4,739% spread Analytics practice
- Correction: Sessionisation Analytics engineering
- Deliberately messy customers, in one paragraph Data quality
- Reader question — When not to build a model Machine learning
- ride-hail-trips.borough: 5 values, 73.6% in the top three Visualization
- units: mean 2, median 1 Statistics
- What ordered_at actually contains in retail-orders Data quality
- The overall average hides 30 different numbers Analytics practice
- Correction: Slowly changing dimension, type 2 Analytics engineering
- What is deliberately wrong with retail-orders Data quality
- Cutting a lesson down — Owning something that runs without you Data platform
- The category that eats the chart Visualization
- revenue_usd: mean 111, median 60 Statistics
- Six things we got wrong, corrected in place Analytics engineering
- What unit_price_usd actually contains in retail-orders Data quality
- The overall average hides 5 different numbers Analytics practice
- Correction: Deduplicate by rank Analytics engineering
- An exercise on clinical-trial Data quality
- Course note — The five tests that cover most questions Experimentation
- data-job-postings.country: 7 values, 69.5% in the top three Visualization
- The average duration min is not the typical one Statistics
- Five minutes with duration_min in ride-hail-trips Data quality
- The overall average hides 4 different numbers Analytics practice
- Correction: Anti-join Analytics engineering
- What is deliberately wrong with ab-test-checkout Data quality
- Course note — When not to build a model Machine learning
- Year three Analytics practice
- The category that eats the chart Visualization
- The average line no is not the typical one Statistics
- Five minutes with account_id in saas-subscriptions Data quality
- bmi by arm: a 0% spread Analytics practice
- Correction: Lookback window Data engineering
- An exercise on sensor-telemetry Data quality
- Cutting a lesson down — Testing data like you test code Data quality
- The category that eats the chart Visualization
- Fifteen minutes a month on the warehouse bill Data platform
- The average first response min is not the typical one Statistics
- Reading reading_at before trusting it in sensor-telemetry Data quality
- salary_max_usd by city: a 427% spread Analytics practice
- Correction: Difference-in-differences Experimentation
- An exercise on flight-delays Data quality
- Course note — Window functions, properly Analytics engineering
- The category that eats the chart Visualization
- The average units is not the typical one Statistics
- Five minutes with subject_id in clinical-trial Data quality
- seats by plan: a 21,443% spread Analytics practice
- Correction: Conditional pivot Analytics engineering
- The question that kills the most projects Analytics practice
- The category that eats the chart Visualization
- An exercise on data-job-postings Data quality
- Cutting a lesson down — Idempotency, backfills, and yesterday arriving twice Data engineering
- The average fare usd is not the typical one Statistics
- Five minutes with city in city-air-quality Data quality
- humidity_pct by status: a 4% spread Analytics practice
- Correction: Baseline before model Machine learning
- World development indicators, in one paragraph Data quality
- Reader question — Window functions, properly Analytics engineering
- clinical-trial.sex: 2 values, 100.0% in the top three Visualization
- Reading flight_no before trusting it in flight-delays Data quality
- The average gdp per capita usd is not the typical one Statistics
- sched_dep_hour by carrier: a 3% spread Analytics practice
- Correction: Median beside the mean Statistics
- Ride-hail trips, in one paragraph Data quality
- Course note — Designing an experiment that can succeed Experimentation
- The category that eats the chart Visualization
- Five minutes with origin in flight-delays Data quality
- The average seats now is not the typical one Statistics
- dep_delay_min by dest: a 38% spread Analytics practice
- Correction: Date spine Analytics engineering
- What is deliberately wrong with ride-hail-trips Data quality
- Course note — Writing SQL people can read, and reading the plan Analytics engineering
- saas-subscriptions.region: 4 values, 93.3% in the top three Visualization
- The average co2 tonnes per capita is not the typical one Statistics
- Five minutes with revenue_usd in retail-orders Data quality
- The overall average hides 3 different numbers Analytics practice
- Factory sensor telemetry, in one paragraph Data quality
- No runbook, no page Data platform
- Cutting a lesson down — Rows, grain, and the shape of a dataset Analytics practice
- The category that eats the chart Visualization
- The average surge multiplier is not the typical one Statistics
- What arr_delay_min actually contains in flight-delays Data quality
- discount_pct by country: a 14% spread Analytics practice
- An exercise on dirty-customers Data quality
- Course note — Schema drift, and the contract that prevents it Data engineering
- data-job-postings.city: 10 values, 41.8% in the top three Visualization
- passengers: mean 2, median 1 Statistics
- Five minutes with passengers in ride-hail-trips Data quality
- discount_pct by category: a 16% spread Analytics practice
- Checkout A/B test, in one paragraph Data quality
- Cutting a lesson down — Joins that do not fan out Analytics engineering
- ab-test-checkout.device: 3 values, 100.0% in the top three Visualization
- The average unit price usd is not the typical one Statistics
- What site actually contains in sensor-telemetry Data quality
- distance_km by payment_type: a 3% spread Analytics practice
- City air quality, in one paragraph Data quality
- Course note — The anatomy of a silent failure Data quality
- city-air-quality.city: 4 values, 75.0% in the top three Visualization
- dep_delay_min: mean 10, median 5 Statistics
- What signed_up_on actually contains in saas-subscriptions Data quality
- The overall average hides 4 different numbers Analytics practice
- The category that eats the chart Visualization
- What is deliberately wrong with support-tickets Data quality
- Cutting a lesson down — Orchestration, and what "it runs every night" costs Data platform
- The average seats is not the typical one Statistics
- What co2_tonnes_per_capita actually contains in world-indicators Data quality
- We turned off 80% of our alerts and caught more incidents Data platform
- salary_max_usd by seniority: a 162% spread Analytics practice
- Customer support tickets, in one paragraph Data quality
- Cutting a lesson down — Causal claims when you cannot randomise Experimentation
- The category that eats the chart Visualization
- distance_km: mean 4.83, median 3.20 Statistics
- What pm25 actually contains in city-air-quality Data quality
- fare_usd by payment_type: a 4% spread Analytics practice
- An exercise on support-tickets Data quality
- Cutting a lesson down — Describing a column without lying Statistics
- world-indicators.region: 5 values, 70.0% in the top three Visualization
- sched_dep_hour by origin: a 4% spread Analytics practice
- Five minutes with opened_at in support-tickets Data quality
- line_no: mean 2, median 1 Statistics
- What is deliberately wrong with dirty-customers Data quality
- Course note — Testing data like you test code Data quality
- The category that eats the chart Visualization
- unit_price_usd: mean 72.66, median 48.86 Statistics
- What humidity_pct actually contains in sensor-telemetry Data quality
- The overall average hides 7 different numbers Analytics practice
- Movie ratings, in one paragraph Data quality
- Reader question — What a data team is actually for Analytics practice
- The category that eats the chart Visualization
- tip_usd: mean 3.13, median 1.96 Statistics
- Five minutes with category in retail-orders Data quality
- The overall average hides 2 different numbers Analytics practice
- What is deliberately wrong with data-job-postings Data quality
- Reader question — Idempotency, backfills, and yesterday arriving twice Data engineering
- The category that eats the chart Visualization
- What flight_no actually contains in flight-delays Data quality
- co2_tonnes_per_capita: mean 3.67, median 2.80 Statistics
- The overall average hides 5 different numbers Analytics practice
- An exercise on ride-hail-trips Data quality
- Course note — What a data team is actually for Analytics practice
- The category that eats the chart Visualization
- The overall average hides 14 different numbers Analytics practice
- Five minutes with priority in support-tickets Data quality
- The average revenue usd is not the typical one Statistics
- What cancelled actually contains in flight-delays Data quality
- Reading subject_id before trusting it in clinical-trial Data quality
- An exercise on city-air-quality Data quality
- Reader question — Causal claims when you cannot randomise Experimentation
- Reading temp_c before trusting it in grid-energy-load Data quality
- sensor-telemetry.status: 3 values, 100.0% in the top three Visualization
- What flight_date actually contains in flight-delays Data quality
- Five minutes with country in world-indicators Data quality
- seats_now: mean 59, median 8 Statistics
- What rated_at actually contains in movie-ratings Data quality
- The overall average hides 14 different numbers Analytics practice
- Reading release_year before trusting it in movie-ratings Data quality
- Retail orders, in one paragraph Data quality
- Reader question — Writing SQL people can read, and reading the plan Analytics engineering
- What dep_delay_min actually contains in flight-delays Data quality
- The category that eats the chart Visualization
- Five minutes with wind_mw in grid-energy-load Data quality
- Five minutes with first_response_min in support-tickets Data quality
- The overall average hides 8 different numbers Analytics practice
- Reading sessions before trusting it in ab-test-checkout Data quality
- Randomised trial results, in one paragraph Data quality
- Course note — Frame the problem, then beat a stupid baseline Machine learning
- What units actually contains in retail-orders Data quality
- ride-hail-trips.payment_type: 3 values, 100.0% in the top three Visualization
- Five minutes with rpm in sensor-telemetry Data quality
- What distance_km actually contains in ride-hail-trips Data quality
- What line_no actually contains in retail-orders Data quality
- seats_now by industry: a 57% spread Analytics practice
- Five minutes with discount_pct in retail-orders Data quality
- An exercise on grid-energy-load Data quality
- Cutting a lesson down — Schema drift, and the contract that prevents it Data engineering
- support-tickets.channel: 4 values, 87.8% in the top three Visualization
- Five minutes with returned in retail-orders Data quality
- age by sex: a 1% spread Analytics practice
- What baseline_score actually contains in clinical-trial Data quality
- What returned actually contains in retail-orders Data quality
- What is deliberately wrong with movie-ratings Data quality
- Reader question — Joins that do not fan out Analytics engineering
- What life_expectancy actually contains in world-indicators Data quality
- Reading carrier before trusting it in flight-delays Data quality
- The category that eats the chart Visualization
- Five minutes with signed_up_on in saas-subscriptions Data quality
- The overall average hides 2 different numbers Analytics practice
- What is deliberately wrong with world-indicators Data quality
- Reading remote before trusting it in data-job-postings Data quality
- Course note — Communicating a result to someone who will not read your notebook Visualization
- Five minutes with arm in clinical-trial Data quality
- flight-delays.origin: 14 values, 22.6% in the top three Visualization
- What channel actually contains in support-tickets Data quality
- What is_returning actually contains in ab-test-checkout Data quality
- salary_min_usd by country: a 379% spread Analytics practice
- An exercise on ab-test-checkout Data quality
- Course note — One metric, one definition Analytics engineering
- Five minutes with flight_date in flight-delays Data quality
- The category that eats the chart Visualization
- Five minutes with adverse_event in clinical-trial Data quality
- The overall average hides 2 different numbers Analytics practice
- Five minutes with o3_ppb in city-air-quality Data quality
- Reading bmi before trusting it in clinical-trial Data quality
- Year two Analytics practice
- Cutting a lesson down — Facts, dimensions, and picking a grain Analytics engineering
- Reading category before trusting it in retail-orders Data quality
- The overall average hides 5 different numbers Analytics practice
- movie-ratings.genre: 8 values, 54.8% in the top three Visualization
- Five minutes with churned_at in saas-subscriptions Data quality
- Reading line_no before trusting it in retail-orders Data quality
- Reading surge_multiplier before trusting it in ride-hail-trips Data quality
- Cutting a lesson down — Features, and explaining what the model did Machine learning
- Five minutes with sex in clinical-trial Data quality
- The category that eats the chart Visualization
- Reading distance_km before trusting it in ride-hail-trips Data quality
- Three dashboards, three revenue numbers, ninety minutes Analytics engineering
- What user_id actually contains in ab-test-checkout Data quality
- mrr_usd by plan: a 13,612% spread Analytics practice
- Five minutes with humidity_pct in sensor-telemetry Data quality
- Cutting a lesson down — Writing SQL people can read, and reading the plan Analytics engineering
- Reading humidity_pct before trusting it in sensor-telemetry Data quality
- flight-delays.carrier: 6 values, 63.6% in the top three Visualization
- Reading country before trusting it in retail-orders Data quality
- Five minutes with dropped_out in clinical-trial Data quality
- The overall average hides 3 different numbers Analytics practice
- What sessions actually contains in ab-test-checkout Data quality
- What resolved_at actually contains in support-tickets Data quality
- data-job-postings.seniority: 5 values, 83.4% in the top three Visualization
- Cutting a lesson down — Choosing the form before the colours Visualization
- Five minutes with carrier in flight-delays Data quality
- Five minutes with queue in support-tickets Data quality
- What tip_usd actually contains in ride-hail-trips Data quality
- no2_ppb by city: a 129% spread Analytics practice
- Five minutes with solar_mw in grid-energy-load Data quality
- The category that eats the chart Visualization
- What posting_id actually contains in data-job-postings Data quality
- Reader question — Orchestration, and what "it runs every night" costs Data platform
- What revenue_usd actually contains in ab-test-checkout Data quality
- What is_holiday actually contains in grid-energy-load Data quality
- Reading pm10 before trusting it in city-air-quality Data quality
- The overall average hides 3 different numbers Analytics practice
- Reading pm25 before trusting it in city-air-quality Data quality
- Cutting a lesson down — Why your query costs what it costs Data platform
- pm10 by city: a 174% spread Analytics practice
- Reading is_holiday before trusting it in grid-energy-load Data quality
- sensor-telemetry.site: 3 values, 100.0% in the top three Visualization
- Five minutes with company_size in data-job-postings Data quality
- The category that eats the chart Visualization
- What city actually contains in data-job-postings Data quality
- Course note — Idempotency, backfills, and yesterday arriving twice Data engineering
- We rewrote our interview loop and the hires got better Analytics practice
- Five minutes with region in world-indicators Data quality
- Five minutes with fare_usd in ride-hail-trips Data quality
- The overall average hides 4 different numbers Analytics practice
- What wind_kph actually contains in city-air-quality Data quality
- Reader question — Choosing the form before the colours Visualization
- Five minutes with plan in saas-subscriptions Data quality
- clinical-trial.arm: 2 values, 100.0% in the top three Visualization
- Five minutes with rated_at in movie-ratings Data quality
- The overall average hides 6 different numbers Analytics practice
- Five minutes with remote in data-job-postings Data quality
- Five minutes with bmi in clinical-trial Data quality
- Course note — Causal claims when you cannot randomise Experimentation
- Reading load_mw before trusting it in grid-energy-load Data quality
- The category that eats the chart Visualization
- Reading pickup_at before trusting it in ride-hail-trips Data quality
- The overall average hides 5 different numbers Analytics practice
- What seats actually contains in saas-subscriptions Data quality
- Five minutes with internet_pct in world-indicators Data quality
- Course note — Monitoring data, not just jobs Data platform
- What mrr_usd actually contains in saas-subscriptions Data quality
- data-job-postings.company_size: 4 values, 81.1% in the top three Visualization
- Reading age before trusting it in clinical-trial Data quality
- gdp_per_capita_usd by country: a 3,670% spread Analytics practice
- Reading flight_date before trusting it in flight-delays Data quality
- Reader question — Schema drift, and the contract that prevents it Data engineering
- Reading payment_type before trusting it in ride-hail-trips Data quality
- Reading region before trusting it in world-indicators Data quality
- seats_now by plan: a 25,267% spread Analytics practice
- The category that eats the chart Visualization
- What remote actually contains in data-job-postings Data quality
- saas-subscriptions.industry: 8 values, 39.8% in the top three Visualization
- Reading units before trusting it in retail-orders Data quality
- Five minutes with seats in saas-subscriptions Data quality
- Reader question — A working setup that will not embarrass you Data engineering
- Reading plan before trusting it in saas-subscriptions Data quality
- What age actually contains in clinical-trial Data quality
- release_year by genre: a 0% spread Analytics practice
- Reader question — Designing an experiment that can succeed Experimentation
- clinical-trial.adverse_event: 4 values, 97.8% in the top three Visualization
- Reading posting_id before trusting it in data-job-postings Data quality
- Five minutes with baseline_score in clinical-trial Data quality
- The overall average hides 5 different numbers Analytics practice
- What queue actually contains in support-tickets Data quality
- Five minutes with site in clinical-trial Data quality
- Cutting a lesson down — Batch, streaming, and the honest difference Data engineering
- clinical-trial.site: 6 values, 52.7% in the top three Visualization
- Five minutes with release_year in movie-ratings Data quality
- The overall average hides 4 different numbers Analytics practice
- What reading_date actually contains in city-air-quality Data quality
- fare_usd by borough: a 229% spread Analytics practice
- What discount_pct actually contains in retail-orders Data quality
- Reader question — The five tests that cover most questions Experimentation
- What passengers actually contains in ride-hail-trips Data quality
- saas-subscriptions.channel: 6 values, 60.9% in the top three Visualization
- Five minutes with mrr_usd in saas-subscriptions Data quality
- Reader question — Features, and explaining what the model did Machine learning
- Five minutes with converted in ab-test-checkout Data quality
- What release_year actually contains in movie-ratings Data quality
- data-job-postings.remote: 3 values, 100.0% in the top three Visualization
- Reading week12_score before trusting it in clinical-trial Data quality
- sessions by variant: a 2% spread Analytics practice
- What country actually contains in retail-orders Data quality
- Reader question — Slowly changing dimensions, and the "as of when" problem Analytics engineering
- Five minutes with tip_usd in ride-hail-trips Data quality
- The category that eats the chart Visualization
- Reading population before trusting it in world-indicators Data quality
- What channel actually contains in saas-subscriptions Data quality
- discount_pct by channel: a 280% spread Analytics practice
- What price_eur_mwh actually contains in grid-energy-load Data quality
- Reader question — Colour is an encoding, not decoration Visualization
- Reading dep_delay_min before trusting it in flight-delays Data quality
- support-tickets.queue: 5 values, 72.2% in the top three Visualization
- What sched_dep_hour actually contains in flight-delays Data quality
- Five minutes with genre in movie-ratings Data quality
- The overall average hides 5 different numbers Analytics practice
- Course note — Facts, dimensions, and picking a grain Analytics engineering
- Reading genre before trusting it in movie-ratings Data quality
- support-tickets.priority: 4 values, 92.6% in the top three Visualization
- Reading company_size before trusting it in data-job-postings Data quality
- The overall average hides 3 different numbers Analytics practice
- Reading region before trusting it in saas-subscriptions Data quality
- retail-orders.channel: 4 values, 83.6% in the top three Visualization
- Five minutes with country in data-job-postings Data quality
- The overall average hides 6 different numbers Analytics practice
- Reading fare_usd before trusting it in ride-hail-trips Data quality
- Cutting a lesson down — Monitoring data, not just jobs Data platform
- retail-orders.country: 8 values, 61.5% in the top three Visualization
- What surge_multiplier actually contains in ride-hail-trips Data quality
- Cutting a lesson down — Correlation, confounding, and Simpson's paradox Statistics
- What carrier actually contains in flight-delays Data quality
- flight_no by origin: a 8% spread Analytics practice
- What revenue_usd actually contains in retail-orders Data quality
- Course note — The first hour with an unfamiliar dataset Data quality
- The category that eats the chart Visualization
- Reading ticket_id before trusting it in support-tickets Data quality
- The overall average hides 2 different numbers Analytics practice
- Five minutes with temp_c in sensor-telemetry Data quality
- Course note — Choosing the form before the colours Visualization
- Reading is_returning before trusting it in ab-test-checkout Data quality
- first_response_min by priority: a 1,095% spread Analytics practice
- What temp_c actually contains in grid-energy-load Data quality
- Reader question — Correlation, confounding, and Simpson's paradox Statistics
- What ticket_id actually contains in support-tickets Data quality
- bmi by site: a 3% spread Analytics practice
- Five minutes with reading_at in sensor-telemetry Data quality
- What pickup_at actually contains in ride-hail-trips Data quality
- Cutting a lesson down — Slowly changing dimensions, and the "as of when" problem Analytics engineering
- What genre actually contains in movie-ratings Data quality
- vibration_mm_s by status: a 191% spread Analytics practice
- What company_size actually contains in data-job-postings Data quality
- Reading year before trusting it in world-indicators Data quality
- Course note — Uncertainty, sampling, and how much to trust a number Statistics
- What load_mw actually contains in grid-energy-load Data quality
- Five minutes with temp_c in grid-energy-load Data quality
- The overall average hides 3 different numbers Analytics practice
- What vibration_mm_s actually contains in sensor-telemetry Data quality
- Reader question — Facts, dimensions, and picking a grain Analytics engineering
- We shipped a Simpson's paradox to the exec team Statistics
- Five minutes with vibration_mm_s in sensor-telemetry Data quality
- seats_now by region: a 20% spread Analytics practice
- What variant actually contains in ab-test-checkout Data quality
- Course note — Describing a column without lying Statistics
- Five minutes with no2_ppb in city-air-quality Data quality
- Five minutes with prior_therapy in clinical-trial Data quality
- rating by genre: a 16% spread Analytics practice
- What churned_at actually contains in saas-subscriptions Data quality
- Cutting a lesson down — Turning a request into a question Analytics practice
- What seats_now actually contains in saas-subscriptions Data quality
- The overall average hides 3 different numbers Analytics practice
- Five minutes with posting_id in data-job-postings Data quality
- Reader question — Communicating a result to someone who will not read your notebook Visualization
- Five minutes with device in ab-test-checkout Data quality
- sched_dep_hour by dest: a 8% spread Analytics practice
- What temp_c actually contains in sensor-telemetry Data quality
- What country actually contains in data-job-postings Data quality
- Cutting a lesson down — One metric, one definition Analytics engineering
- Five minutes with trip_id in ride-hail-trips Data quality
- seats by industry: a 53% spread Analytics practice
- Reading solar_mw before trusting it in grid-energy-load Data quality
- Cutting a lesson down — The anatomy of a silent failure Data quality
- The overall average hides 14 different numbers Analytics practice
- Reading hour_at before trusting it in grid-energy-load Data quality
- Cutting a lesson down — A working setup that will not embarrass you Data engineering
- What dropped_out actually contains in clinical-trial Data quality
- mrr_usd by region: a 21% spread Analytics practice
- Reading prior_therapy before trusting it in clinical-trial Data quality
- Course note — Reading a result without fooling yourself Experimentation
- The overall average hides 6 different numbers Analytics practice
- Reading temp_c before trusting it in city-air-quality Data quality
- Course note — Turning a request into a question Analytics practice
- baseline_score by site: a 4% spread Analytics practice
- What pm10 actually contains in city-air-quality Data quality
- Course note — What a pipeline is really doing Data engineering
- What reopened actually contains in support-tickets Data quality
- The overall average hides 5 different numbers Analytics practice
- Year one Analytics practice
- Reader question — Frame the problem, then beat a stupid baseline Machine learning
- Reading queue before trusting it in support-tickets Data quality
- The overall average hides 6 different numbers Analytics practice
- Five minutes with distance_km in ride-hail-trips Data quality
- Course note — Validation that matches deployment Machine learning
- Reading exposed_on before trusting it in ab-test-checkout Data quality
- Reading no2_ppb before trusting it in city-air-quality Data quality
- sessions by device: a 3% spread Analytics practice
- Reading signed_up_on before trusting it in saas-subscriptions Data quality
- Reader question — Owning something that runs without you Data platform
- The overall average hides 6 different numbers Analytics practice
- What reading_at actually contains in sensor-telemetry Data quality
- Cutting a lesson down — What a pipeline is really doing Data engineering
- What site actually contains in clinical-trial Data quality
- Ten months in, what writing the course has taught us Analytics engineering
- The overall average hides 4 different numbers Analytics practice
- What week12_score actually contains in clinical-trial Data quality
- Cutting a lesson down — Communicating a result to someone who will not read your notebook Visualization
- What converted actually contains in ab-test-checkout Data quality
- mrr_usd by industry: a 49% spread Analytics practice
- What priority actually contains in support-tickets Data quality
- Reader question — Uncertainty, sampling, and how much to trust a number Statistics
- Five minutes with sessions in ab-test-checkout Data quality
- The overall average hides 5 different numbers Analytics practice
- Reading returned before trusting it in retail-orders Data quality
- humidity_pct by site: a 0% spread Analytics practice
- Cutting a lesson down — Frame the problem, then beat a stupid baseline Machine learning
- Five minutes with revenue_usd in ab-test-checkout Data quality
- temp_c by status: a 26% spread Analytics practice
- Five minutes with posted_on in data-job-postings Data quality
- Cutting a lesson down — When not to build a model Machine learning
- Five minutes with status in sensor-telemetry Data quality
- Course note — Why your query costs what it costs Data platform
- Reading csat before trusting it in support-tickets Data quality
- salary_max_usd by country: a 379% spread Analytics practice
- Reader question — The anatomy of a silent failure Data quality
- Reading opened_at before trusting it in support-tickets Data quality
- bmi by sex: a 1% spread Analytics practice
- Reading sched_dep_hour before trusting it in flight-delays Data quality
- Five minutes with ticket_id in support-tickets Data quality
- The overall average hides 4 different numbers Analytics practice
- Five minutes with payment_type in ride-hail-trips Data quality
- The overall average hides 6 different numbers Analytics practice
- Five minutes with hour_at in grid-energy-load Data quality
- salary_min_usd by seniority: a 162% spread Analytics practice
- Five minutes with pm10 in city-air-quality Data quality
- flight_no by carrier: a 3% spread Analytics practice
- Reading passengers before trusting it in ride-hail-trips Data quality
- The overall average hides 3 different numbers Analytics practice
- Reading seniority before trusting it in data-job-postings Data quality
- The overall average hides 2 different numbers Analytics practice
- What exposed_on actually contains in ab-test-checkout Data quality
- The overall average hides 4 different numbers Analytics practice
- Reading site before trusting it in sensor-telemetry Data quality
- Reader question — The first hour with an unfamiliar dataset Data quality
- Five minutes with industry in saas-subscriptions Data quality
- The overall average hides 3 different numbers Analytics practice
- What adverse_event actually contains in clinical-trial Data quality
- Cutting a lesson down — The five tests that cover most questions Experimentation
- The overall average hides 4 different numbers Analytics practice
- Five minutes with week12_score in clinical-trial Data quality
- The overall average hides 30 different numbers Analytics practice
- Five minutes with seats_now in saas-subscriptions Data quality
- The overall average hides 4 different numbers Analytics practice
- What rating actually contains in movie-ratings Data quality
- Reader question — One metric, one definition Analytics engineering
- Five minutes with ordered_at in retail-orders Data quality
- age by arm: a 1% spread Analytics practice
- Reading temp_c before trusting it in sensor-telemetry Data quality
- The overall average hides 5 different numbers Analytics practice
- Reading tip_usd before trusting it in ride-hail-trips Data quality
- The overall average hides 8 different numbers Analytics practice
- Reader question — Batch, streaming, and the honest difference Data engineering
- revenue_usd by device: a 28% spread Analytics practice
- Reading cancelled before trusting it in flight-delays Data quality
- Cutting a lesson down — Validation that matches deployment Machine learning
- What gdp_per_capita_usd actually contains in world-indicators Data quality
- Cutting a lesson down — Colour is an encoding, not decoration Visualization
- duration_min by borough: a 254% spread Analytics practice
- Reading o3_ppb before trusting it in city-air-quality Data quality
- unit_price_usd by channel: a 6% spread Analytics practice
- Five minutes with site in sensor-telemetry Data quality
- distance_km by borough: a 331% spread Analytics practice
- Cutting a lesson down — Window functions, properly Analytics engineering
- temp_c by site: a 3% spread Analytics practice
- Five minutes with surge_multiplier in ride-hail-trips Data quality
- year by country: a wide spread Analytics practice
- Five minutes with load_mw in grid-energy-load Data quality
- The overall average hides 3 different numbers Analytics practice
- Five minutes with arr_delay_min in flight-delays Data quality
- revenue_usd by category: a 1,000% spread Analytics practice
- What internet_pct actually contains in world-indicators Data quality
- Reader question — Validation that matches deployment Machine learning
- Five minutes with unit_price_usd in retail-orders Data quality
- Cutting a lesson down — Uncertainty, sampling, and how much to trust a number Statistics
- We deleted 34 dashboards and nobody complained Visualization
- Reading revenue_usd before trusting it in retail-orders Data quality
- vibration_mm_s by site: a 29% spread Analytics practice
- Reading trip_id before trusting it in ride-hail-trips Data quality
- The overall average hides 6 different numbers Analytics practice
- Reading status before trusting it in sensor-telemetry Data quality
- The overall average hides 30 different numbers Analytics practice
- Reading revenue_usd before trusting it in ab-test-checkout Data quality
- The overall average hides 10 different numbers Analytics practice
- What year actually contains in world-indicators Data quality
- Course note — Batch, streaming, and the honest difference Data engineering
- The overall average hides 3 different numbers Analytics practice
- Reading city before trusting it in data-job-postings Data quality
- duration_min by payment_type: a 3% spread Analytics practice
- Cutting a lesson down — The patterns that keep coming up Analytics engineering
- Five minutes with co2_tonnes_per_capita in world-indicators Data quality
- The overall average hides 14 different numbers Analytics practice
- Course note — Owning something that runs without you Data platform
- population by region: a 63% spread Analytics practice
- Five minutes with salary_min_usd in data-job-postings Data quality
- The overall average hides 4 different numbers Analytics practice
- Five minutes with gdp_per_capita_usd in world-indicators Data quality
- Reader question — What a pipeline is really doing Data engineering
- The overall average hides 14 different numbers Analytics practice
- Reading co2_tonnes_per_capita before trusting it in world-indicators Data quality
- pm25 by city: a 173% spread Analytics practice
- What account_id actually contains in saas-subscriptions Data quality
- Reader question — Testing data like you test code Data quality
- Five minutes with pm25 in city-air-quality Data quality
- Course note — Orchestration, and what "it runs every night" costs Data platform
- The overall average hides 8 different numbers Analytics practice
- Reading origin before trusting it in flight-delays Data quality
- Reader question — Why your query costs what it costs Data platform
- The overall average hides 4 different numbers Analytics practice
- Reading priority before trusting it in support-tickets Data quality
- Course note — Correlation, confounding, and Simpson's paradox Statistics
- revenue_usd by country: a 12% spread Analytics practice
- What csat actually contains in support-tickets Data quality
- The overall average hides 3 different numbers Analytics practice
- The meeting where the median won Statistics
- Course note — Slowly changing dimensions, and the "as of when" problem Analytics engineering
- Five minutes with reading_date in city-air-quality Data quality
- The overall average hides 4 different numbers Analytics practice
- Five minutes with resolved_at in support-tickets Data quality
- Reader question — Monitoring data, not just jobs Data platform
- Reading channel before trusting it in retail-orders Data quality
- year by region: a wide spread Analytics practice
- Five minutes with city in data-job-postings Data quality
- baseline_score by arm: a 0% spread Analytics practice
- What solar_mw actually contains in grid-energy-load Data quality
- The overall average hides 8 different numbers Analytics practice
- Five minutes with dep_delay_min in flight-delays Data quality
- The overall average hides 8 different numbers Analytics practice
- What salary_min_usd actually contains in data-job-postings Data quality
- The overall average hides 6 different numbers Analytics practice
- Reading country before trusting it in world-indicators Data quality
- Reader question — Describing a column without lying Statistics
- Reading converted before trusting it in ab-test-checkout Data quality
- unit_price_usd by category: a 1,012% spread Analytics practice
- What first_response_min actually contains in support-tickets Data quality
- The notebook that only ran once Machine learning
- Why we started writing this down Analytics practice