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Hypothesis Testing and Inference Questions

Fundamental framework and application of hypothesis testing and statistical inference. Topics include formulating null and alternative hypotheses, understanding Type I and Type II errors, interpreting p values and confidence intervals, selecting and applying common tests such as t tests, chi square tests, analysis of variance, and non parametric alternatives, checking test assumptions, and discussing statistical versus practical significance. Candidates should explain power, significance levels, effect sizes, and common pitfalls such as misinterpreting p values or violating independence assumptions. At more advanced levels, discuss limitations of null hypothesis significance testing, alternatives such as Bayesian inference, and guidance for when different approaches are appropriate.

EasyTechnical
26 practiced
A stakeholder reads a t-test and says 'p=0.04 means there's a 96% chance our feature works.' As a data analyst, explain precisely what the p-value indicates, list three common misinterpretations, and outline how you would communicate the result to non-technical stakeholders.
HardTechnical
30 practiced
Your analytics dashboard tracks dozens of critical metrics daily (MAU, DAU, retention, revenue). Design a statistical monitoring strategy that balances sensitivity to real changes with control of false alarms. Discuss thresholds, multiple testing corrections, and alerting cadence.
HardTechnical
30 practiced
Design an interrupted time series (ITS) analysis to evaluate the impact of a site redesign deployed on a specific date. Outline the statistical model (segmented regression), necessary diagnostics (autocorrelation, seasonality), and how to test for a sustained level or slope change. Describe implementation in Python/statsmodels.
HardTechnical
25 practiced
A PM wants to peek at daily p-values during an experiment and stop once p<0.05. Explain why optional stopping inflates Type I error and propose statistically sound strategies to allow interim looks (e.g., alpha spending, group-sequential methods, Bayesian monitoring).
HardTechnical
33 practiced
A product manager suggests checking multiple metrics mid-experiment until one shows significance, and then reporting that metric. As a data analyst, how would you respond to this suggestion? Outline ethical and statistical risks, propose a policy and technical safeguards the analytics team should adopt to prevent p-hacking, and suggest educational steps for the organization.

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