Find the mean variance and standard deviation for this data

Find the mean , variance, and standard deviation for this data set:NEED HELP

15, 9, 9, 8, 9

1. The mean is ? I think it is 10

2. The variance is ?

3. The standard deviation is ? Round to two decimal places as needed

x = 15 9 9 8 9

x^2 225 81 81 64 81

X total = 50

x^2 total = 532

Mean = 50/5 =10

Var(x) = E(X^2) -10^2

= 532/5 -100

= 106.4-100

= 6.4

3) std dev = 2.53