# True to assume equal variance when testing difference between the means???

#### wanye

##### New Member
hi all,

In testing for the difference between the means, is it true that we assume that each of the populations is normally distributed with equal variances? why?

#### JohnM

##### TS Contributor
I think people get into the "habit" of assuming normality and equal variances because the violations of these assumptions need to be pretty severe before they will lead us to erroneous conclusions.