Question

What is the mathematical formula for the pooled variance of two populations?

Answer 1

`V_p = ((n_1-1)s_1^2 +(n_2-1)s_2^2)/(n_1+n_2-2)`

Explanation:

The pooled standard deviation is given by
`S_p = sqrt(((n_1-1)s_1^2 +(n_2-1)s_2^2)/(n_1+n_2-2))`

for variance remove the sqare root operator

`V_p = ((n_1-1)s_1^2 +(n_2-1)s_2^2)/(n_1+n_2-2)`