Test #2 Review

Chapters 8 - 12

These are practice problems to help you prepare for Test #2. If you complete and submit the review on Blackboard by the Sunday before Test #2, I will give you 2 points extra credit towards the test. Solutions to the review will be posted the day after it's due for you to check your work. Your answers can be typed or handwritten. If you print and handwrite your answers, you will need to scan in solutions.

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1. Identify each of the following as a Parameter or a Statistics:

1. In a survey of a sample of Canadian Adults, 65% support legalizing marijuana. _____________

1. The heights of all the basketball players at Michigan State University. ____________________

1. The total number of grammatical errors for all the books at the National Library. ____________

1. A sample of MLB starting pitchers resulted in a mean ERA of 3.84. _____________________

1. Identify which sampling method was used in each of the following:

{Hint: The sampling methods we learned about are Simple Random (SRS), Stratified, Cluster, Systematic, Convenience, or Voluntary Response}

1. Law enforcement officials use a radar gun to measure the speed of every tenth vehicle on an interstate.

1. A study on attitudes about smoke is conducted at a college. The students are divided by class {freshman, sophomore, junior, and senior}. Then a random sample is selected from each class and interviewed.

1. In order to assess the opinion of students at the Ohio State University on campus snow removal, a reporter for the student newspaper interviews the first 20 students he meets on campus that day.

1. Calling randomly generated telephone numbers, a study asked 800 U.S. adults which medical conditions could be prevented by their diet.

1. A radio DJ wants to know listeners opinion of the new Shinedown album, so he asks them to call or write in their opinions.

1. Of the six sampling methods we learned {Simple Random (SRS), Stratified, Cluster, Systematic, Convenience, or Voluntary Response}which two are biased? Explain.

1. Newsweek conducted a poll of 850 American adults and found that 196 have a SiriusXM radio in their vehicle.

1. Let prepresent the population proportion of American adults that have SiriusXM radio. What statistic would we use to estimate p? Calculate that statistic.

1. Find a 95% confidence interval for p.

1. Find a 99% confidence interval for p.

1. Write a sentence interpreting your 99% confidence interval in the context of this problem.

1. What is the margin of error for the 95% confidence interval and the 99% confidence interval?

1. Which confidence interval is wider (the 95% or the 99% confidence interval)? ___________

1. USA Todayreported that about 47% of the general consumer population in the United States is loyal to the automobile manufacturer of their choice. Suppose that Chevrolet did a study of a random sample of 1065 Chevrolet owners and found that 518 said that they would buy another Chevrolet. Test the claim by Chevrolet that the population proportion of consumers loyal to its product is more than 47%.

Use = 0.05 level of significance.

1. State the null and alternate hypotheses.

1. Does this problem meet all the assumptions and conditions needed to perform a hypothesis test? Explain.

1. Find the test statistic and the decision reached based on the test statistic. (Use the Rejection Region Method)

1. Give the P-value and the decision reached based on the P-value. (Use the P-value Method)

1. Summarize the final conclusion in the context of the claim.

1. Suppose that you live near a McDonald's restaurant and you want to estimate, with 95% confidence, the population proportion of all people in your neighborhood who go to McDonald's on a typical day. Your estimatemust be within a distance of 0.03 from the population proportion p.

1. How many people should you include in your sample if you use the preliminary estimate that nationally about 1 in 20 (5%) of all Americans go to McDonald's on a typical day?

1. How many people should you include in your sample if there is no preliminary estimate of what proportion of Americans go to McDonald's on a typical day?
   1. Use this information to compute a 95% confidence interval for the population mean room rate of all Denver area hotel and motel rooms.

1. A sociologist is studying marriage customs in a rural community in Denmark. The sociologist wants to estimate the population mean age of a woman at the time of her first marriage within 0.25 years. How many women should be included in the sample to construct a 99% confidence interval for the population mean? Assume that the population standard deviation is 2.7 years.

1. The Wall Street Journalstated that the average cost of a room (hotel or motel) in the Denver area was $140 per night. Suppose that you are a reporter for a local competing paper and you question the statement by The Wall Street Journal. Suppose that you used the Yellow Pages to get a random sample of 40 hotels and motels in the Denver area. The sample average room rate was $128.75. Assume that the population standard deviation $15.91.

1. Do you suspect that The Wall Street Journalfigure might be high or low based upon your confidence intervals from above?Explain.

1. State the null and alternate hypotheses you would use to test your theory from part b.

1. Find the test statistic and the P-value.

1. Using either the rejection region or p-value method when decision about the null hypothesis would you come to?

1. Summarize the final conclusion in the context of the claim. Does this test support you answer to part b?

1. Let x be a random variable that represents hemoglobin count (HC) in grams per 100 milliliters of whole blood. Then x has a distribution that is approximately normal with a population mean of 15 for healthy adult women. Suppose a female has taken 14 lab blood tests during the past year. The HC data sent to the patient's doctor were:

19	21	15	21	18	17	15
14	20	19	16	13	19	14

Use an = 0.05 significance level to test the claim by the patient's doctor that the population HC for this patient is higher than 15.

1. State the null and alternate hypotheses.

1. Give the test statistic and the decision reached based on the test statistic. (Use the Rejection Region Method)

1. Give the P-value and the decision reached based on the P-value. (Use the P-value Method)

1. Summarize the final conclusion in the context of the claim.

1. If after completing this test and coming to a conclusion, I find out I made a Type I Error, what would that mean in context to this problem?