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Probability and Statistical Inference Questions

Covers fundamental probability theory and statistical inference from first principles to practical applications. Core probability concepts include sample spaces and events, independence, conditional probability, Bayes theorem, expected value, variance, and standard deviation. Reviews common probability distributions such as normal, binomial, Poisson, uniform, and exponential, their parameters, typical use cases, computation of probabilities, and approximation methods. Explains sampling distributions and the Central Limit Theorem and their implications for estimation and confidence intervals. Presents descriptive statistics and data summary measures including mean, median, variance, and standard deviation. Details the hypothesis testing workflow including null and alternative hypotheses, p values, statistical significance, type one and type two errors, power, effect size, and interpretation of results. Reviews commonly used tests and methods and guidance for selection and assumptions checking, including z tests, t tests, chi square tests, analysis of variance, and basic nonparametric alternatives. Emphasizes practical issues such as correlation versus causation, impact of sample size and data quality, assumptions validation, reasoning about rare events and tail risks, and communicating uncertainty. At more advanced levels expect experimental design and interpretation at scale including A B tests, sample size and power calculations, multiple testing and false discovery rate adjustment, and design choices for robust inference in real world systems.

HardTechnical
0 practiced
Derive the sampling distribution of the sample mean for i.i.d. random variables with mean μ and variance σ^2. Show the mean and variance of the sampling distribution and explain implications for estimator consistency.
HardTechnical
0 practiced
Derive the Wald test statistic for a single parameter estimate (e.g., coefficient β) and explain interpretation. Discuss scenarios where the Wald test performs poorly and alternatives you would use.
HardTechnical
0 practiced
You suspect data collection bias where certain user segments are underrepresented. Explain how to test for sampling bias statistically and one method to adjust analyses or model training to account for unequal representation.
HardTechnical
0 practiced
Explain likelihood ratio tests and how they are used to compare nested models. In an ML setting, when would you prefer a likelihood ratio test over information criteria (AIC/BIC)?
EasyTechnical
1 practiced
List common probability distributions (normal, binomial, Poisson, uniform, exponential) and give one ML or production example use-case for each distribution.

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