MA 260 MA260 STATISTICAL ANALYSIS I EXAM 8 ANSWERS (2021) - ASHWORTH
Ashworth MA260 Statistical Analysis I Exam 8 Answers (2021)
1. A fleet of rental cars - all the same make, model, and year - has a mean fuel efficiency of 23.4 miles per gallon (mpg). A random sample of 41 cars are selected and the air filter of each is replaced with a new one. Let μ be the population mean fuel efficiency score that would occur if every car's air filter were replaced. The air filter change is deemed effective if . A test is made of versus .
2. In a simple random sample of size 88, there were 22 individuals in the category of interest. It is desired to test H0: p = 0.31 versus H1: p < 0.31. Compute the test statistic z.
3. In a simple random sample of size 75, there were 19 individuals in the category of interest. It is desired to test versus . Do you reject H0 at the 0.01 level?
4. In a study to determine whether counseling could help people lose weight, a sample of people experienced a group-based behavioral intervention, which involved weekly meetings with a trained interventionist for a period of six months. The following data are numbers of pounds lost for 14 people.
5. A test of versus is performed using a significance level of . The value of the test statistic is . Is H0 rejected?
6. A grocery store owner claims that the mean amount spent per checkout is more than . A test is made of H0: μ = 85 versus H1: μ > 85. The null hypothesis is not rejected. State the appropriate conclusion.
7. Use technology to find the P-value for the following values of the test , sample , and alternate hypothesis H1.
8. In a simple random sample of 77 families, the mean number of children is 2.2 with a standard deviation of 0.9. You wish to determine if the population mean differs from 2.1 children per family.
9. Find the critical value for the following values of the significance , sample , and alternate hypothesis H1.
10. The following display from a TI-84 Plus calculator presents the results of a hypothesis test for a population proportion p.
11. A sample of 39 students enroll in a program that claims to improve scores on the quantitative reasoning portion of the Graduate Record Examination (GRE). The participants take a mock GRE test before the program begins and again at the end to measure their improvement.
12. A market research firm reported that the mean annual earnings of all family practitioners in the United States was $179,574. A random sample of 38 family practitioners in New York that month had mean earnings of = $198,513 with a standard deviation of $35,113. You wish to test whether family practitioners in New York make more than the national average.
13. The Golden Comet is a hybrid chicken that is prized for its high egg production rate and gentle disposition. According to recent studies, the mean rate of egg production for 1-year-old Golden Comets is 5.6 eggs/week.
14. The following display from a TI-84 Plus calculator presents the results of a hypothesis test for a population mean μ.
15. The following output from MINITAB presents the results of a hypothesis test.
16. The following display from a TI-84 Plus calculator presents the results of a hypothesis test for a population mean μ.
17. The mean annual tuition and fees for a sample of 8 private colleges was with a standard deviation of . A dotplot shows that it is reasonable to assume that the population is approximately normal. You wish to test whether the mean tuition and fees for private colleges is different from .
18. The following output from MINITAB presents the results of a hypothesis test for a population mean μ.
19. The following output from MINITAB presents the results of a hypothesis test.
20. In a simple random sample of size 98, there were 37 individuals in the category of interest. Compute the sample proportion .
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