試題詳解

40. Figure [A] demonstrates a normal distribution of English midterm performance of Eagle class students. The statistical data shows that students’ mean score is 70 points, with a standard deviation of 10 points. There are 30 students in Eagle class. Based on the data and the graph, which of the following statement is     TRUE    ?
(A) w= 55, x=60, y=80, z=90
(B) Twenty-five students in Eagle Class scored above 60 and passed the English midterm exam.
(C) Students who scored within the 90-100 range were as many as students who scored within the 50-60 range.
(D) According to the graph, we are 95 percent certain that individual student’s actual score will be within one standard error of 70 points. W X M Y Z