SAT Performance. The Scholastic Aptitude Test (SAT) contains three areas: critical reading, mathematics, and writing. Each area is scored on an 800 -point scale. A sample of SAT scores for six students follows.
$$
\begin{array}{cccc}
\text { Student } & \begin{array}{c}
\text { Critical } \\
\text { Reading }
\end{array} & \text { Mathematics } & \text { Writing } \\
1 & 526 & 534 & 530 \\
2 & 594 & 590 & 586 \\
3 & 465 & 464 & 445 \\
4 & 561 & 566 & 553 \\
5 & 436 & 478 & 430 \\
6 & 430 & 458 & 420
\end{array}
$$
a. Using a . 05 level of significance, do students perform differently on the three areas of the SAT?
b. Which area of the test seems to give the students the most trouble? Explain.