Question 971712
10, 0, 10, 16, 7, 18, 0.25, 5, 10, and 28

sum is 104.25.  
Divide by 10 is the mean=10.425

Standard deviation:  8.51

It is the sum of the squared deviations from the mean divided by 9.

(10-10.425)^2 +....(28-10.425)^2/9