But why you equalize S with the standard error (S.E.)?

Question

In the formulae of Sp, S_1^2 and S_2^2 it refers to standard deviation of each population, why you equalize to the standard error?.

Thanks for your time Johnny!!!

Answer 1

I assume they were sample standard deviations instead of s. e. s. Otherwise, the variances seemed to be a little bit too different. But you can simply change Tue formulas to reflect they are s. e. s.