9. Hypothesis Testing for One Sample

A teacher claims her students’ average test score is 75. A researcher suspects it’s different. A sample of 25 students has a mean score of 78 with a standard deviation of 6.

$\left(A\right)$ Create a $90\%$ confidence interval for the mean test score.

A teacher claims her students’ average test score is 75. A researcher suspects it’s different. A sample of 25 students has a mean score of 78 with a standard deviation of 6.

$\left(B\right)$ At the $0.10$ significance level, test the claim.