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Technology. In Exercises 9鈥�12, test the given claim by using the display provided from technology. Use a 0.05 significance level. Identify the null and alternative hypotheses, test statistic, P-value (or range of P-values), or critical value(s), and state the final conclusion that addresses the original claim.

Airport Data Speeds Data Set 32 鈥淎irport Data Speeds鈥� in Appendix B includes Sprint data speeds (mbps). The accompanying TI-83/84 Plus display results from using those data to test the claim that they are from a population having a mean less than 4.00 Mbps. Conduct the hypothesis test using these results.

TV Viewing. According to Communications Industry Fore cast & Report, published by Veronis Suhler Stevenson, the average person watched $4.55$hours of television per day in $2005$. A random sample of $20$people gave the following number of hours of television watched per day for last year.

At the $10\%$significance level, do the data provide sufficient evidence to conclude that the amount of television watched per day last year by the average person differed from that in $2005$? (Note: $\overline{x}=4.760hours,s=2.297hours$)

Death Rolls. Alligators perform a spinning maneuver, referred to as a "death roll," to subdue their prey, Videos were taken of juvenile alligators performing this maneuver in a study for the article "Death Roll of the Alligator, Mechanics of Twist and Feeding in Water" (Journal of Experimental Biology, Vol. $210,\mathrm{pp}.2811-2818)$by F. Fish et al. One of the variables measured was the degree of the angle between the body and head of the alligator while performing the roll. A sample of $20$rolls yielded the following data, in degrees.

At the $5\%$significance level, do the data provide sufficient evidence to conclude that, on average, the angle between the body and head of an alligator during a death roll is greater than $45掳?$

(Note: $\stackrel{炉}{x}=49.0$and $s=10.0$)

Iron Deficiency? Iron is essential to most life forms and to normal human physiology. It is an integral part of many proteins and enzymes that maintain good health. Recommendations for iron are provided in Dietary Reference Intakes, developed by the Institute of Medicine of the National Academy of Sciences. The recommended enzymes that maintain good health. Recommendations for iron are provided in Dietary Reference Intakes, developed by the Institute of Medicine of the National Academy of Sciences. The recommended dietary allowance (RDA) of iron for adult females under the age of 51 years is 18 milligrams (mg) per day. A hypothesis test is to be performed to decide whether adult females under the age of 51 years are, on average, getting less than the RDA of 18 mg of iron.

Early-Onset Dementia. Dementia is the loss of the intellectual and social abilities severe enough to interfere with judgment, behavior, and daily functioning. Alzheimer's disease is the most common type of dementia. In the article "Living with Early Onset Dementia: Exploring the Experience and Developing Evidence Based Guidelines for Practice" (Alzheimer's Care Quarterly, Vol. 5, Issue 2, pp. 111-122), P. Harris and J. Keady explored the experience and struggles of people diagnosed with dementia and their families. A hypothesis test is to be performed to decide whether the mean age at diagnosis of all people with early-onset dementia is less than 55 years old.

Refer to Exercise 9.20. Explain what each of the following would mean.

a. Type I error

b. Type II error

c. Correct decision

Now suppose that the results of carrying out the hypothesis test lead to rejection of the null hypothesis. Classify that conclusion by error type or as a correct decision if in fact the mean post-work heart rate of casting workers

d. equals the normal resting heart rate of 72 bpm.

e. exceeds the normal resting heart rate of 72 bpm.

What role does the decision criterion play in a hypothesis test?

Teacher Salaries. Refer to Exercise 9.22. Explain what each of the following would mean.

a. Type I error

b. Type II error

c. Correct decision

Now suppose that the results of carrying out the hypothesis test lead to nonrejection of the null hypothesis. Classify that conclusion by error type or as a correct decision if in fast the mean salary of classroom teachers in Ohio

d. equals the national mean of \(55.4 thousand.

e. exceeds the national mean of \)55.4 thousand.

This exercise contain graphs portraying the decision criterion for a one-mean 2-test. The curve in each graph is the normal curve for the test statistic under the assumption that the null hypothesis is true. For each exercise, determine the

a. rejection region.

c. critical value(s).

b. nonrejection region.

d. significance level.

e. Construct a graph similar to that in Fig. 9.3 on page 361 that depicts your results from parts (a)-(d).

f. Identify the hypothesis test as two tailed, left tailed or right tailed.