We need to use the variance and standard deviation for a sample:
The equation for a variance is:

Where x⁻ is the mean of x and n is the total number of values.
First, let us find the mean:

Then :

Now, we can find the variance:
![s^2=(\Sigma x-30.5)/(10-1)=((38-30.5)+(45-30.5)+(27-30.5)+(42-30.5)+(17-30.5)+(36-30.5)+(10-30.5)+(21-30.5)+(33-30.5)+(36-30.5))/(9)]()
Simplify it:

Now, we need to use the next formula to find the standard deviation:

Then:
![s=\sqrt{((38-30.5)^2+(45-30.5))^2+(27-30.5))^2+(42-30.5))^2+(17-30.5))^2+(36-30.5))^2+(10-30.5))^2+(21-30.5))^2+(33-30.5))^2+(36-30.5))^2)/(9)}]()
Then, the standard deviation is:
