statistics
posted by Amy .
In a population of exam scores,a score of X= 48 corresponds to z= 1 and a score of X= 36 corresponds to z= .50. Find the mean and standard deviation for the population?

zscore = (xmean)/sd
1 = (48m)/s
s = 48m
s+m = 48 , #1
1/2 = (36m)/s
(1/2)s = 36m
s = 72  2m
2m  s = 72 , #2
add #1 and #2
3m = 120
m = 40
then s+40 = 48
s = 8
mean = 40 , SD = 8