Now the sum of squares would be squaring the 10, 3, 8, 0, and 4 and then dividing by 4 (take one out for sampling error) correct?

Now the mean would be 25/5 (sum of x over n) which is five.

Taking out variance it would become Sigma(25 (sum of x) - 5 (mean) squared over n-1 (5-1=4)

So the variance would be 20 squared (400) over four, leaving me with a variance of 100? That doesn't seem quite right to me. Do I have to square root it again to make the s squared into s?