Question

Two sections of a class took the same quiz. Section A had 15 students who had a mean score of 80, and section B had 20 students who had a mean score of 90. Overall, what was the approximate mean score for all the students on the quiz?

A. 84.3
B. 85
C. none of these
D. cannot be determined

Answer 1

B, because when you add 90+80 you get 170 and 170/2 = 85

Answer 2

Option B. 85

Explanation:

Two sections of a class took the same quiz.

Mean score of section A of 15 students = 80

Mean score of section B of 20 students = 90

We will calculate the approximate mean score for all the students.

The pool mean is the mean of means of two or more groups. We will find it by this formula =
`\frac{\text{sum of means}}{\text total number of groups}`

=
`(80+90)/(2)`

= 85

The approximate mean score for all the students on the quiz was 85.