Nine Students Took the SAT Test

Essay

Nine students took the SAT test. Their scores are listed below. Later, they took a test preparation course and retook the SAT. Their new scores are listed below. Use the Wilcoxon signed rank test to test the claim that the test preparation had no effect on their scores. Use α = .05. $$\begin{array} { l c c c c c c c c c } \hline \text { Student } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 \\\hline \text { Before Score } &1000 & 850 & 890 & 830 & 900 & 810 & 820 & 1080 & 980 \\\text { After Score } & 1020 & 850 & 880 & 870 & 930 & 820 & 810 & 1120 & 1000 \\\hline\end{array}$$