A Harris poll was taken to determine which of 13 major industries are doing a good job of serving their customers. Among the industries rated most highly by Americans for serving their customers were computer hardware and software companies, car manufacturers, and airlines. The industries rated lowest on serving their customers were tobacco companies, managed care providers, and health insurance companies. Seventy-one percent of those polled responded that airlines are doing a good job serving their customers. Suppose due to rising ticket prices, a business analyst feels that this figure is now too high. He takes a poll of464Americans, and324say that the airlines are doing a good job of serving their customers. Let alpha equal0.05.

a.Does the survey show enough evidence to declare that the proportion of Americans saying that the airlines are doing a good job of serving their customers is significantly lower than stated in the Harris poll?

b.If the researcher fails to reject the null hypothesis and if the figure is actually69% now, what is the probability of committing a Type II error?

c.What is the probability of committing a Type II error if the figure is really67%?

d.What is the probability of committing a Type II error if the figure is really55%?

Appendix A Statistical Tables

(Round the intermediate values to 4 decimal places, e.g. 0.1254. Round the values of z to 2 decimal places, e.g. 15.25. Round your answer to 4 decimal places, e.g. 0.1254.)

Click here to open Table A.5

Forpa=0.60z=0.683-0.60(0.60)(0.40)463=3.65

From Table A.5, the area for z = 3.65 is essentially, 0.5000

The probability of committing a Type error = 0.5000 - 0.5000 = 0.000

a.The value of the test statistic isz=_______________________ (enter the value of test statistic rounded to 2 decimal places)and we(select a decision)

fail to reject the null hypothesis OR reject the null hypothesis.

b.______________________ (enter probability rounded to 4 decimal places)

c.______________________ (enter probability rounded to 4 decimal places)

d.______________________ (enter probability rounded to 4 decimal places)