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)? (Points : 24)
8. (TCO D) Engineering studies show that it is feasible to install a windmill for generating electrical power if the mean wind speed is greater than 14 mi per hour (mph). The Piedmont Electric Co-op is considering locating mulls at the top of Mount Hunter. A random sample of 45 wind speed readings yields the following results.
Sample Size = 45
Sample Mean = 14.9 mph
Sample Standard Deviation = 3.8 mph
Does the sample data provide sufficient evidence to conclude that installation is feasible at this location (using a = .10)? 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 sufficient evidence to conclude that installation is feasible at this location (using a = .10)? (Points : 24)
1. (TCO E) McCave Development Enterprises is considering whether to build a shopping mall in Statesville. The manager wants you to analyze the relationship between mall size and the rate of return on invested capital. You select a random sample of 16 cities similar to Statesville in demographic and economic characteristics and collect the following data on FOOTAGE (in 10,000 square feet) and RETURN (rate of return as a %).

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