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Statistics & ExperimentsPro

Design experiments that survive real scrutiny.

A/B Testing & Experimentation

Go from causal question to production experiment with hypotheses, metrics, sample size, randomization, diagnostics, CUPED, sequential testing, and bandits.

What you will leave with

You can write an experiment plan, calculate its requirements, diagnose broken assignment, analyze results, and communicate a defensible decision.

Modules
8
Duration
~8 hours
Level
Beginner to Advanced
Access
Module 1 free
  • Browser-native scipy & statsmodels
  • CUPED & sequential testing
  • Capstone end-to-end

What you will be able to do

What this course prepares you to do.

The curriculum is organized around these 4 practical outcomes.

Turn a product question into a falsifiable hypothesis

Define primary, secondary, and guardrail metrics

Plan sample size and detect randomization failures

Apply variance reduction and sequential methods responsibly

Curriculum

Every module earns the next one.

Open a module to inspect every section before you start. Your progress follows you through the course.

01
Module 1

Why Experiment? The Causal Inference Mindset

BeginnerFree preview

Correlation vs causation, The counterfactual, Random assignment, and more.

View 5 sections
  1. 1Correlation Lies (and Dashboards Lie with It)
  2. 2The Counterfactual: The Only Question That Matters
  3. 3Random Assignment: The Most Powerful Tool You Have
  4. 4When NOT to A/B Test
  5. 5Setting Up Bean & Brew's Free-Shipping Test
60 min5 sections
Open module
02
Module 2

Hypothesis & Metric Design (OEC + Guardrails)

BeginnerPro

Hypothesis writing, OEC primary metric, Secondary metrics, and more.

View 5 sections
  1. 1Writing a Falsifiable Hypothesis
  2. 2The OEC: Picking the Primary Metric
  3. 3Secondary Metrics: Explaining Mechanism
  4. 4Guardrail Metrics: What You Cannot Break
  5. 5Leading vs Lagging Indicators
65 min5 sections
Open module
03
Module 3

Statistical Foundations Refresh

IntermediatePro

Null hypothesis, p-values, Confidence intervals, and more.

View 5 sections
  1. 1The Null Hypothesis (and Why It Is Weird)
  2. 2p-values: What They Actually Claim
  3. 3Confidence Intervals: The Better Story
  4. 4Type I & Type II Errors
  5. 5Two-Sample Tests: t-test, z-test, proportion test
55 min5 sections
Open module
04
Module 4

Sample Size & Power Analysis

IntermediatePro

Statistical power, Effect size (MDE), Sample size formulas, and more.

View 5 sections
  1. 1The Four Knobs (Effect, Alpha, Power, Variance)
  2. 2Sample Size for Proportions
  3. 3Sample Size for Means and Ratio Metrics
  4. 4The Minimum Detectable Effect (MDE)
  5. 5Trade-offs: Duration vs Detection vs Cost
55 min5 sections
Open module
05
Module 5

Randomization & Bucketing

IntermediatePro

Random assignment, Deterministic hashing, Sticky vs session-level, and more.

View 5 sections
  1. 1Why Random Assignment Beats Everything
  2. 2Deterministic Hashing: The Production Pattern
  3. 3Sticky vs Per-Session Assignment
  4. 4SRM: The Sample Ratio Mismatch Canary
  5. 5Carryover Effects & Experiment Isolation
55 min5 sections
Open module
06
Module 6

Reading Results & Avoiding Pitfalls

IntermediatePro

Peeking problem, Multiple testing, Simpson's paradox, and more.

View 5 sections
  1. 1The Peeking Problem (False-Positive Inflation)
  2. 2Multiple Testing Correction (Bonferroni, Benjamini-Hochberg)
  3. 3Simpson's Paradox in Experiments
  4. 4Novelty & Primacy Effects
  5. 5Segment Analysis: Where the Real Story Hides
55 min5 sections
Open module
07
Module 7

Variance Reduction & Faster Experiments

AdvancedPro

Variance is the enemy, CUPED, Stratification, and more.

View 5 sections
  1. 1Why Variance is the Enemy
  2. 2CUPED: Pre-Experiment Data Saves You
  3. 3Stratification & Post-Stratification
  4. 4Sequential Testing (Peeking, but Legal)
  5. 5Combining CUPED + Sequential: Production Patterns
55 min5 sections
Open module
08
Module 8

Beyond Standard A/B: The Frontier

AdvancedPro

Multi-armed bandits, Switchback experiments, Bayesian A/B, and more.

View 5 sections
  1. 1Multi-Armed Bandits: When Equal Exposure is Wrong
  2. 2Switchback Experiments: Marketplaces & Network Effects
  3. 3Bayesian A/B: The Probability-of-Win Framing
  4. 4Quasi-Experiments: When You Cannot Randomize
  5. 5Capstone: Bean & Brew Free-Shipping Test End-to-End
55 min5 sections
Open module

Who this course is for

Built for people who need to use the skill.

Start with the background you have. The prerequisite notes above tell you exactly what is assumed.

01

Product and data analysts

02

Data scientists responsible for experimentation

03

PMs and engineers who review test results

Start the course

Begin with Why Experiment? The Causal Inference Mindset.

Module 1 introduces the language and example used throughout the rest of the course.

Open Module 1
A/B Testing & Experimentation, Master Causal Inference, CUPED, Bandits | Interactive Course (Module 1 Free) | Let's Data Science