One-Sample T-Interval For Paired Data

Computing two separate confidence intervals for pre-test and post-test scores and then taking their difference.

Ignoring the paired nature of the data and treating the two tests as independent samples.

Using a z-interval assuming the population variance is known.

Using data from 30 students in an SAT preparation class where the improvement (post-test minus pre-test) has a mean of $42.25$ and a sample standard deviation of $27.92$ to construct a 90% confidence interval of approximately $(33.59, 50.91)$.