calculate the mean of the set of boys and girls below:
boys 21, 18, 20, 16, 16, 22, 28, 24, 26
girls 13, 16, 15, 14, 15, 19, 22, 26, 12
A-boys: 21.22 girls: 16.89
b-boys, 21 girls, 15
c-boys 18.5 girls 17
d-boys 18.5 girls 15
