Posted by Debin on .
Consider the following test scores obtained by a class.
Test score
90
80
70
60
50
Frequency
1
4
11
6
2
Find the standard deviation (rounded to the nearest hundredth).

Math 
PsyDAG,
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.