Question

What is the standard deviation of {1, 2, 3, 4, 5}?

Answer 1

The answer is `6`.

Explanation:

Note that the formula of variance for calculation purpose is

`1/n sum_(i=1) ^n x_i^2 - (1/n sum_(i=1)^n x_i)^2`

where `n` is the total number of values in the given data set.
In your given data we have `n = 5` and the values of `x_i`'s are `{1,2,3,4,5}` .

So, your variance `= 1/5 [ 1^2+2^2+ 3^2 +4^2+5^2] - (1/5 *[ 1+2+3+4+5])^2`
`= 11 -9`
`=6`