Dr. Whoosy Whatsit is conducting an experiment to test whether the consumption o

Question

Dr. Whoosy Whatsit is conducting an experiment to test whether the consumption of french fries is related to happiness. 100 students are randomly selected for the experiment. Each student is instructed to eat 3 ounces of french fries (about the equivalent of a small order at McDonald's) 3 times a week for 4 weeks. They then complete a happiness survey. The national average on the happiness survey is µ = 23 with a standard deviation of ? = 6. Using ? < .05, the critical values of z for this experiment are ±1.96.

a. What is the expected value of M for the distribution of sample means for this test?

b. What is the standard error for the distribution of sample means for this test?

c. Is this a one or two-tailed test?

d. The 100 students had an average happiness score of M = 24.3. What is the z-score for this sample mean? (Round to two decimals.)

e. Comparing the test statistic calculated in (d) with the critical values of z for this experiment, does the sample fall into the critical region of the distribution of sample means? (Enter yes or no.)

f. What is your decision regarding the null hypothesis?

Explanation / Answer

a) expected value of M=23

b)standard error =?/sqrt(n)=6/sqrt(100)=0.60

c) as we are checking if happiness average changed irrespective of left or right direction; this is two tailed test

d) z-score for this sample mean =(X-mean)/std error =(24.3-23)/0.6=2.17

e)as test statistic is higher than criitcal value 1.96 ; hence it falls in critical region (Yes)

f)reject the null hypothesis

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