Statistics (STAT 101) Confidence Intervals + Hypothesis Tests Formula Sheet and Practice Problems
University of Illinois Urbana-Champaign
Statistics (STAT 101) | Practice Problems

Overview
A one-stop stats packet for finals: CI and hypothesis test setups, decision rules, and practice problems that force correct conditions, symbols, and interpretations.

Key topics
•z vs t intervals and tests
•one-sample and two-sample mean/proportion setups
•p-value and critical value workflow
•type I/II error and power intuition
•checking conditions (randomness, normality, independence)

Suggested study tasks
•build 8 confidence intervals with correct interpretation
•run 8 hypothesis tests with stated H0/Ha
•decide one- vs two-sided from context
•compute a p-value from a test statistic
•write one conclusion sentence in context

Common pitfalls
•treating CI overlap as a formal test
•mixing alpha and p-value
•using z when sigma is unknown
•writing conclusions without context or direction