Author Question: A sample of 30 cookies is taken to test the claim that each cookie contains at least 9 chocolate ... (Read 77 times)

newyorker26 · **on:** Jun 24, 2018

A sample of 30 cookies is taken to test the claim that each cookie contains at least 9 chocolate chips. The average number of chocolate chips per cookie in the sample was 7.8 with a standard deviation of 3.
a. State the null and alternative hypotheses.
b. Using the critical value approach, test the hypotheses at the 5 level of significance.
c. Using the p-value approach, test the hypothesis at the 5 level of significance.
d. Compute the probability of a Type II error if the true number of chocolate chips per cookie is 8.

Question 2

A carpet company advertises that it will deliver your carpet within 15 days of purchase. A sample of 49 past customers is taken. The average delivery time in the sample was 16.2 days. The standard deviation of the population () is known to be 5.6 days.
a. State the null and alternative hypotheses.
b. Using the critical value approach, test to determine if their advertisement is legitimate. Let = .05.
c. Using the p-value approach, test the hypotheses at the 5 level of significance.

sierrahalpin · **Reply #1 on:** Jun 24, 2018

Answer to Question 1

a. H0: 9
Ha: < 9
b. test statistic t = -2.190 < -1.699; reject H0
c. reject H0; the p-value is between .01 to .025
d. A Type II error has not been committed since H0 was rejected.

Answer to Question 2

a. H0: 15
Ha: > 15
b. test statistic Z = 1.5 < 1.645; therefore do not reject H0
c. Do not reject H0; p-value is (.5 - .4332) = 0.0668