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Statistical Foundations for Experimentation Questions

Core statistical concepts and inference needed to design analyze and interpret experiments. Topics include hypothesis testing p values confidence intervals Type One and Type Two errors the relationship between sample size variability and interval width statistical power minimum detectable effect and effect size versus practical significance. Candidates should be able to choose and explain common statistical tests such as t tests and chi square tests contrast Bayesian and frequentist approaches at a conceptual level and describe variance estimation and variance reduction techniques. The topic covers corrections for multiple comparisons sequential testing and the risks of peeking and p hacking common misconceptions about p values and limitations of inference such as confounding and selection bias. Candidates should also be able to translate statistical findings into clear language for non technical stakeholders and explain uncertainty and limitations.

EasyTechnical
50 practiced
Explain the formal difference between a 95% confidence interval (frequentist) and a 95% credible interval (Bayesian). Provide a small numeric illustration (no code required) showing how the two intervals could differ and explain why those differences matter when communicating uncertainty to non-technical stakeholders.
HardTechnical
50 practiced
Derive the variance of the difference-in-means estimator for a completely randomized experiment under the Neyman finite-population framework. Then show the standard large-sample sample-size formula for detecting an absolute difference delta with power 1 - beta and significance alpha. State all assumptions and show intermediate algebraic steps.
HardTechnical
58 practiced
You will run an experiment with up to 4 interim analyses plus a final analysis. Describe how to construct an alpha-spending plan using O'Brien–Fleming and Pocock boundaries. Explain how to choose between them, show how to compute nominal alphas at each look (conceptually), and discuss practical implementation steps and limitations including required simulations and software choices.
EasyTechnical
52 practiced
List common data types encountered in experiments (continuous, binary, count, time-to-event) and for each list at least two statistical tests or modeling approaches you would consider (e.g., t-test, linear regression, logistic regression, Poisson/negative-binomial, survival analysis). For each choice describe typical diagnostics you would run to validate model assumptions.
HardTechnical
60 practiced
Researchers often search data, select promising effects, and report significant results (p-hacking). Explain the statistical consequences of post-selection inference and describe methods to correct or mitigate selection bias: selective inference frameworks, data-splitting (honest inference), knockoffs, and multiverse analysis. Propose practical workflow changes for a research team to minimize false discoveries while enabling exploration.

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