When You Are Testing Whether Two Population Means of Two

Multiple Choice

When you are testing whether two population means of two normally distributed populations differ and the population variances are both unknown but unequal, the t test statistics will usually have a non-integer number of degrees of freedom v.In this case, you should:

A) round down to the previous integer.
B) round up to the next integer.
C) assume that the population variances are equal and use v = n1 + n2 - 2.
D) change the sample sizes until the number of degrees of freedom is an integer.