試題詳解

3. A teacher finds that final grad es in the statistics department are distributed as: A, 25%； B, 25%； C, 40%； D, 5%； F, 5%. At the end of a randomly selected semester, the following grades were recorded, Calculate the chi-square test statistic X² used to determine if the grade distribution for the departrnent is different than expected. Use a = 0.01.

(A)4.82
(B)6.87
(C)3.41
(D)5.25