i. If the null hypothesis states that there is no difference between the mean income of males and the mean income of females, then the test is one-tailed.
Ii) If we are testing for the difference between two population means, it is assumed that the sample observations from one population are independent of the sample observations from the other population.
Iii) When sample sizes are less than 30, a test for the differences between two population means has n
- 1 degrees of freedom.
A) (i), (ii) and (iii) are all correct statements
B) (i) and (ii) are correct statements, but not (iii).
C) (i) and (iii) are correct statements but not (ii).
D) (ii) and (iii) are correct statements but not (i).
E) (ii) is a correct statement, but not (i) and (iii).

Question

Quizplus · Accepted Answer

The null hypothesis stating no difference between means suggests a two-tailed test. Independence of samples is assumed when testing differences between two means. Degrees of freedom for small samples is typically n1 + n2 - 2, not n - 1.

I If the Null Hypothesis States That There Is No