QM110 / QM210

Confidence Interval Challenge

Given sample data from real business scenarios, construct the 95% confidence interval and see if it captures the true population mean.

You will face 10 business scenarios with sample statistics (n, x̄, s)
For each scenario, enter the lower and upper bounds of your 95% CI
The correct CI uses: x̄ ± t* · (s / √n) with df = n − 1
10 points if your CI captures the true mean and is close to the correct width
5 points if your CI captures the true mean but is too wide
0 points if your CI misses the true mean entirely
After all 10 rounds, see your score, grade, and a CI visualization

95% Confidence Interval Formula

x̄ ± t*_{0.025, df} · (s / √n)

Challenge Complete!

You scored out of 100

of 10 intervals captured the true mean