Below Are the Data of an Course That Prepares Students

Short Answer

Below are the data of an course that prepares students for standardized testing. The data below show pretest (test on day 1) and a post test (test after taking the course) scores of students who enrolled. Use this data to answer the following questions.
$$\begin{array} { c c } \hline \text { Pretest } & \text { Posttest } \\\hline 650 & 720 \\580 & 640 \\590 & 680 \\760 & 770 \\590 & 580 \\620 & 650 \\740 & 720 \\580 & 610 \\690 & 670 \\610 & 650 \\620 & 630 \\640 & 680 \\590 & 670 \\\hline\end{array}$$ Calculate the 95% confidence interval for the mean difference