Statistics · Module 7 · Confidence intervals

Confidence Intervals Walkthrough

Watch 100 intervals from 100 random samples and see about 95 of them capture the true mean, then build z, t and proportion intervals step by step, see how confidence level and sample size change the width, and plan a sample size. Go at your own pace. Nothing here is graded.

Speed

Think of it like this

Quick check

Wrong answers are fine here. Read why, then try again.

Dr. Akash Garg · Statistics Study Tools · CC BY-NC-SA 4.0
Use the left and right arrow keys to move between steps. Practice next in the Confidence Intervals Lab. Every data set here uses made-up practice numbers chosen to look realistic; they are not clinical reference values. Critical values come from an accurate normal CDF and an accurate Student t CDF, rounded to three decimal places so they match printed z and t tables.