statistics
posted by kim .
A survey of 40 clothing stores reported these numbers of sales held during a random,ly selected year

A survey of 40 clothing stores reported these numbers of sales held during a randomly selected year
1115,1620,2125,2630, 3135, 3640 and the frequencies are 3,5,12,9,8,3 Caculate the mean variance and standard deviation 
Find the mean first = sum of scores/number of scores
Subtract each of the scores from the mean and square each difference. Find the sum of these squares. Divide that by the number of scores to get variance.
Standard deviation = square root of variance
I'll let you do the calculations.