Question

STATISTICS Statisticians use the formula σ = √v to calculate a standard deviation σ, where v is the variance of a data set. Find the variance when the standard deviation is 15.

Answer 1

If σ = the standard deviation and we know the deviation is 15 we can set his up like the following:

σ = √v 
15 = √v
Square both sides:
$15^2 = \sqrt{v}^2$
$225 = v$
$v = 225$