Answer:
The complete question is attached.
To find the variance and deviation, we have to use their definition or formulas:
Standard deviation.

So, first we have to find the difference between each number and the mean:
76-81=-5
87-81=6
65-81=-16
88-81=7
67-81=-14
84-81=3
77-81=-4
82-81=1
91-81=10
85-81=4
90-81=9
Now, we have to elevate each difference to the squared power and then sum all:

Then, we replace in the formula:

Variance.
The variance is just the squared power of the standard deviation. So:
