To find the standard deviation:
1.) Organize the data into a table.
2.) Determine the mean (to find the mean, add all the terms and divide them by their number)
3.) Subtract the mean from each score.
4.) After you have subtracted them all, add all the differences.
5.) Divide them sum by their number. (34)
6.) Find the square root.
(This is the correct way on how to find the standard deviation if I am not mistaken)
Formula:
SQUARE ROOT OF Sum of ( x - mean)
_______________
number of terms