Direct Mailing Company sells computer hardware and software over the Internet. The company claims that at least 90% of all orders are mailed within 72 hours after they are received. A random sample of 150 orders showed that 129 were mailed within 72 hours. Does the sample data provide evidence to conclude that less than 90% of all orders are mailed within 72 hours (with a = .01)? Use the hypothesis testing procedure outlined below.
a. Formulate the null and alternative hypotheses.
b. State the level of significance.
c. Find the critical value (or values), and clearly show the rejection and nonrejection regions.
d. Compute the test statistic.
e. Decide whether you can reject Ho and accept Ha or not.
f. Explain and interpret your conclusion in part e. What does this mean?
g. Determine the observed p-value for the hypothesis test and interpret this value. What does this mean?
h. Does the sample data provide evidence to conclude that less than 90% of all orders are mailed within 72 hours (with a = .01)?