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Stats & probability

Distributions → inference → experiments → regression → causal

Why this sequence

Build the foundations (distributions and MLE), master frequentist vocabulary (CI, p-value, power), then walk through experiment design, A/B pitfalls, and regression-based causal reasoning. The final third integrates everything on Ads-scale production problems.

38 questions · 0 mastered · 0 in review
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  1. 01
    Binomial Distribution — Probability of Fewer Than 2 Girls Out of N Children
    Q090 Medium High freq
    New
  2. 02
    How Would You Prove a Sequence Follows a Uniform Distribution?
    Q001 Medium High freq
    New
  3. 03
    Poisson vs. Binomial — Assumptions, When to Use Each, and the Poisson Approximation
    Q101 Medium High freq
    New
  4. 04
    Derive the Conditional Distribution Y | X for a Bivariate Normal
    Q062 Hard High freq
    New
  5. 05
    Derive the MLE for Normal(μ, σ²) from Scratch
    Q061 Hard High freq
    New
  6. 06
    Truncated Normal — Estimate μ and σ² When You Only Observe X > 3
    Q060 Hard Medium freq
    New
  7. 07
    Censored Normal — Estimate μ, σ² When X > 10 Is Right-Censored
    Q078 Hard High freq
    New
  8. 08
    Explain CI, P-value, and Alpha — How Would You Explain Them to a PM?
    Q003 Medium High freq
    New
  9. 09
    Testing a Population Mean — What Does p-value = x% Actually Mean?
    Q055 Medium High freq
    New
  10. 10
    Why Can't We Reverse the Null Hypothesis to "Prove" Something?
    Q004 Hard High freq
    New
  11. 11
    How Does a Data Scientist Decide the P-Value Cutoff?
    Q051 Medium High freq
    New
  12. 12
    How Do You Choose Between 99% and 95% Confidence Level?
    Q008 Medium High freq
    New
  13. 13
    Your SE is 0.1, You Want SE = 0.01 — What Do You Do? What If Sample Size Can't Change?
    Q056 Hard High freq
    New
  14. 14
    Given a Sample X₁, …, Xₙ ~ X, Estimate P(X > 10) and Construct a 95% CI
    Q057 Hard High freq
    New
  15. 15
    How Does Bootstrap Work? Can It Be Used for Variance Reduction?
    Q002 Medium High freq
    New
  16. 16
    Compute a P-Value from the Definition via Monte Carlo Simulation — No Formulas
    Q069 Medium High freq
    New
  17. 17
    Drug A (Placebo) vs B — Between-Subjects vs Within-Subjects Design
    Q077 Medium High freq
    New
  18. 18
    Drug Trial — Parallel vs Crossover Design (Detailed Follow-ups)
    Q089 Hard High freq
    New
  19. 19
    Designing an Experiment for an Android App Update (Self-Selection Bias)
    Q006 Hard High freq
    New
  20. 20
    Experiment Where Users Must Sign an Agreement — Selection Bias and How to Fix It
    Q086 Hard High freq
    New
  21. 21
    CRM Algorithm A/B Test — Identifying Wrong CI Calculation & Proper Experiment Design
    Q075 Hard High freq
    New
  22. 22
    30 A/B Tests, One Significant at p = 0.04 — Should You Ship?
    Q041 Medium High freq
    New
  23. 23
    Novelty and Primacy Effects — How to Detect Them and What to Do
    Q095 Medium High freq
    New
  24. 24
    The Peeking Problem — Why Early Stopping Inflates False Positives, and How to Fix It
    Q094 Hard High freq
    New
  25. 25
    Network Effects and Spillover — Why User-Level A/B Breaks and How to Fix It
    Q096 Hard High freq
    New
  26. 26
    Incrementality Testing — Measuring What Ads Actually Cause, Not Just What They're Credited For
    Q097 Hard High freq
    New
  27. 27
    Explain Linear Regression to a Non-Technical Person
    Q027 Hard High freq
    New
  28. 28
    What Happens If You Duplicate Data in Linear Regression?
    Q020 Medium High freq
    New
  29. 29
    The Four Assumptions of Linear Regression — What Breaks When Each Is Violated, and How to Diagnose
    Q099 Medium High freq
    New
  30. 30
    Why Is the Test on a Regression Coefficient a t-Distribution, Not Normal?
    Q071 Hard High freq
    New
  31. 31
    Does OLS Give the Same Predictions If You Rotate the Features?
    Q072 Hard High freq
    New
  32. 32
    Lasso vs. Ridge — When to Use Which, and Why Lasso Creates Sparsity
    Q100 Medium High freq
    New
  33. 33
    Relationship Between Product Sales and Review Data
    Q032 Medium High freq
    New
  34. 34
    Does YouTube Ad Playback Drive Sales? Spot the Problems in This Simple Regression
    Q067 Medium High freq
    New
  35. 35
    Does Listening to the YouTube Music "Commute" Playlist Make People Drive Faster?
    Q073 Hard High freq
    New
  36. 36
    A Campaign Launched in One Country — Did It Actually Cause the Metric Lift?
    Q040 Hard High freq
    New
  37. 37
    Global Sales Went Up — But Could Regional Analysis Show It Went Down?
    Q043 Medium High freq
    New
  38. 38
    Bad Search Algorithm A/B Test — Three-Part Analysis
    Q044 Hard High freq
    New