Question

In testing for differences between the means of two independent populations, the null hypothesis is

Question 21 options:

A)	H0 : μ1 - μ2 = 0.

B)	H0 : μ1 - μ2 = 2.

C)	H0 : μ1 - μ2 < 2.

D)	H0 : μ1 - μ2 > 0.

In testing for the differences between the means of 2 independent populations where the variances in each population are unknown but assumed equal, the degrees of freedom are

Question 22 options:

A)	n1 + n2 - 1.

B)

n - 1.

C)	n1 + n2 - 2.

D)

n - 2.

Answer 1

For hypothesis testing differences between the means of two independent populations means we are testing whether there is any difference between two means. But as null hypothesis always have equality sign. So hypothesis is

which implies

So answer is A.

For testing the differences between means of 2 indendent will have ni-1 df for there respective group

Hence for testing for the differences between the means of 2 independent populations degree of freedom is n1+n2-2

So answer is C n1+n2-2