Question

A psychiatrist is studying the effect of a certain antidepressant medication on serotonin levels in the brain. The psychiatrist randomly assigns 32 of her patients to take medication and 32 patients to not take medication. At the end of one month, the psychiatrist records the serotonin levels of patients. Suppose the psychiatrist correctly conducts a test of significance. The test shows a statistically significant difference in average serotonin levels for the two groups of patients. What conclusion can the psychiatrist draw from these results?

a. there is not enough evidence that patients who take a certain antidepressant medication have different serotonin levels in the brain than patients who are not taking any medication

b. the sample size may be too small to trust the results from a hypothesis test

c. There is enough evidence that patients who take a certain antidepressant medication have different serotonin levels in the brain than patients who are not taking any medication

Answer 1

It is given in the question that the test shows a statistically significant difference in average serotonin levels for the two groups of patients

this means that there is sufficient evidence to conclude that there is a statistically significant difference between the serotonin levels between two groups.

Statistically significant results means the result of significant test must have a significant p value, i.e. the p value must be less than significance level.

so, option C is correct

There is enough evidence that patients who take a certain antidepressant medication have different serotonin levels in the brain than patients who are not taking any medication