Mann-Whitney U-toets

Stel, je bent Analytics Engineer bij een start-up in een vroege fase, waar het websiteverkeer nog klein is. Omdat je in veel gevallen de tests lang moet laten lopen om genoeg data te verzamelen voor de aannames van parametrische tests, kan het nodig zijn om te leunen op niet-parametrische tests om sneller beslissingen te nemen.

Eén van die tests is de Mann-Whitney U-toets: een significantietoets om te bepalen of twee onafhankelijke steekproeven uit een populatie met dezelfde verdeling komen. Je gebruikt deze toets om het verschil in time_on_page tussen twee groepen in de checkout-gegevens te analyseren. De DataFrame checkout is beschikbaar en pingouin is al geladen, samen met pandas en numpy.

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A/B-testen in Python

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# Calculate the mean and count of time on page by variant
print(checkout.____('checkout_page')['____'].____({'____', '____'}))

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Deze oefening maakt deel uit van de cursus

A/B-testen in Python

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In this chapter, you’ll learn the foundations of A/B testing. You’ll explore clear steps and use cases, learn the reasons and value of designing and running A/B tests, and discover the most commonly used metrics design and estimation frameworks.

Exercise 1: What is A/B testing?Exercise 2: When an A/B test is not best Exercise 3: A/B testing steps Exercise 4: Randomization effects Exercise 5: Why run experiments?Exercise 6: Correlation visualization Exercise 7: Correlation or causation?Exercise 8: Metrics design and estimation Exercise 9: Means and proportions Exercise 10: Ad impressions metrics

In Chapter 2, you’ll cover the experiment design process. Starting with learning how to formulate strong A/B testing hypotheses, you’ll also cover statistical concepts such as power, error rates, and minimum detectable effects. You’ll finish the chapter by learning to estimate the appropriate sample size needed to yield conclusive results and tackle scenarios with multiple comparisons.

Exercise 1: Hypothesis formulation and distributions Exercise 2: Strong hypothesis formulation Exercise 3: Plotting distributions Exercise 4: Central limit theorem for means Exercise 5: Experimental design: setting up testing parameters Exercise 6: Interpreting p-values Exercise 7: Error rates in the wild Exercise 8: Experimental design: power analysis Exercise 9: Plotting power curves Exercise 10: Sample size for means Exercise 11: Sample size for proportions Exercise 12: Multiple comparisons tests Exercise 13: Is a multiple comparisons correction needed?Exercise 14: Corrected p-values

Here, you’ll discover a concrete workflow for cleaning, preprocessing, and exploring AB testing data, as well as learn the necessary sanity checks we need to follow to ensure valid results. You’ll explore a detailed explanation and example of analyzing difference in proportions A/B tests.

Exercise 1: Data cleaning and exploratory analysis Exercise 2: Proportions EDA Exercise 3: A/B test data cleaning Exercise 4: Sanity checks: Internal validity Exercise 5: SRM Exercise 6: Distributions balance Exercise 7: Sanity checks: external validity Exercise 8: Novelty effects detection Exercise 9: Simpson's paradox in action Exercise 10: Analyzing difference in proportions A/B tests Exercise 11: Difference in proportions A/B test Exercise 12: Interpretation of confidence intervals Exercise 13: Confidence intervals for proportions

In the final chapter, you’ll develop frameworks for analyzing differences in means and leveraging non-parametric tests when several assumptions aren't met. You’ll also learn how to apply the Delta method when analyzing ratio metrics and discover the best practices and some advanced topics to continue the A/B testing mastery journey.

Exercise 1: Verschillen in gemiddelden in A/B-tests analyseren Exercise 2: T-test voor verschil in gemiddelden Exercise 3: Paarsgewijze t-toetsen Exercise 4: Niet-parametrische statistische toetsen Exercise 5: Parametrisch of niet-parametrisch?Exercise 6: Mann-Whitney U-toets

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Exercise 7: Chi-kwadraattoets voor onafhankelijkheid Exercise 8: Ratiometrieken en de delta-methode Exercise 9: Delta of niet?Exercise 10: Delta-methode Exercise 11: Intro: best practices en geavanceerde onderwerpen voor A/B-testen Exercise 12: Best practices Exercise 13: Dag-van-de-week-effect Exercise 14: Afronding: A/B-testen in Python