Question 1. Suppose that a researcher is interested to see if an exercise program affects body weight among men. In the population, the mean adult body weight for men is = 195.5 pounds, = 42. The researcher takes a sample of n = 25 men and measures their weight after 15 weeks of the exercise program and finds the average weight is M = 192.5.

Step 1: State your hypotheses(use alpha = .05)

a. Based on the prompt above, should this be a one-tailed or two-tailed test? Why?

State the hypotheses using notation and in words

b. Null:

c. Alternative:

Step 2: Find your critical region.

Step 3: Compute test statistic(z_M)

Step 4: Make a decision

Should you "reject the null hypothesis" or "fail to reject the null hypothesis"? Why?

Step 5: Interpret the results

Step 6: Compute the effect size (cohen's d)

Question 2. Screen time and use of social media are related to negative mental health outcomes, including suicidal thoughts. In a national survey of adolescents, the mean number of depressive symptoms was = 2.06, = 1. A researcher wants to determine if in-person social interaction decreases depressive symptoms. The researcher recruitsn = 25participants and instructs them to visit friends or family instead of using social media. The researcher observes that the average number of depressive symptoms isM = 1.66after the intervention.

Step 1: State your hypotheses(use alpha = .05)

a. Based on the prompt above, should this be a one-tailed or two-tailed test? Why?

State the hypotheses using notation and in words

b. Null:

c. Alternative:

Step 2: Find your critical region.

Step 3: Compute test statistic(z_M)

Step 4: Make a decision

Should you "reject the null hypothesis" or "fail to reject the null hypothesis"? Why?

Step 5: Interpret the results

Step 6: Compute the effect size (cohen's d)