Question

Mrs. Gifford's class consists of 15 girls and 25 boys.

On the first test the mean of the girls’ scores was 80 and the mean of the boy’s scores was 70. What was the class mean? (Remember the class mean is not just averaging the two means)

Answer 1

mean = ∑x/n

Girl's 80 = ∑x/15

x = 1200

Boy's 70 = ∑x/25

x = 1750

Class mean = (1200+1750)/(15+25) = ?

Answer 2

(80*15 + 70*25)/(40)