A psychologist is interested in determining whether a new treatment for depression improves (decreases) depression scores. She randomly assigns 30 subjects to the treatment and 30 subjects to the control. At the conclusion of the study she uses an independent t-test to evaluate whether the groups differ on a widely used depression scale that ranges between 0 and 30. The treatment group mean is 18 and the control group mean is 22. What is the null hypothesis for the analysis

Mean Hypothesis is Mean values of the treatment and the control group is not equal

Step-by-step explanation:

The null hypothesis is mostly the problem statement.

Here the problem statement is

To check whether there is a difference in treatment result of two groups of patient; one which has received the treatment and the other is the control group.

Thus, the null hypothesis is

H0 - Mean values of the treatment and the control group is not equal

2 is the final ! : )

the answer is d. 75%