RES 342 Final Exam ( A+ Solution )
1) What are the critical z-values for a two-tailed hypothesis test if the significant level = 0.01?
A. ± 1.96
B. ± 2.33
C. ± 2.58
D. ± 1.65
2) In classical hypothesis testing, the test statistic is to the critical value what the __________.
A. ‘p-value' is to alpha
B. critical value is to alpha
C. test statistic is to the ‘p-value'
D. level of significance is to the test statistic
3) For a hypothesis test of a single population mean at 95% confidence level, a calculated Z score of 1.7 supports the conclusion that
A. the population mean is greater than the hypothesized value
B. the null hypothesis cannot be rejected
C. the sample is biased
D. the population mean is less than expected
4) If the paired differences are normal in a test of mean differences, then the distribution used for testing is the
A. normal distribution
C. student distribution
D. F distribution
5) One hundred women were polled and 60 reported successfully communicating an automobile problem to an auto repairman. A sample of 150 men had 95 reporting the same success. The value of the test statistic for a test of the equality of proportions is
6) Weekly sales of iPods® at 20 Best Buy® stores are compared before and after installing a new eye-catching display. To determine if the display is effective in increasing sales, what type of statistical test would you perform?
A. Comparison of means using independent samples using a t-test
B. Comparison of proportions using independent samples using a z-test
C. Comparison of means using a paired z-test
D. Comparison of means using a paired t-test
7) When is it appropriate to use the paired difference t-test?
A. Four samples are compared at once.
B. Any two samples are compared.
C. Two independent samples are compared.
D. Two dependent samples are compared.
8) A survey of hotels found that the average hotel room rate in New Orleans is $88.42 and the average room rate in Phoenix is $80.61. The survey sampled 50 hotels in each city. The standard deviations were $5.62 and $4.83, respectively. At alpha=.05, it can be concluded that there is a significant different in the rates?
9) If the paired differences are normal in a test of mean differences, the distribution used for testing is the
A. normal distribution
C. student t distribution
D. F distribution
10) The accountant for Thomas's Furniture Store is concerned regarding the outstanding receivable owed the company. There has been a cash flow problem and it is believed that the slow collection of accounts receivable is partially the blame. The accountant believes that 40% of the present accounts are more than 4 months behind in making payments. To be able to make a decision regarding this belief, a random sample of 100 accounts was taken. It was found that 37 accounts were more than 4 months late. Did the sample data confirm the accountant's belief? Use the .05 significant level for the statistical test.
A. There is not enough evidence to confirm or deny the belief.
B. The accountant's belief is not confirmed.
C. The accountant's belief is confirmed.
D. The accountant needed to take a larger sample.
11) New college business graduates are finding it difficult to get a job. A business journal has reported that only one in five graduates is able to find a job within 6 months of their graduation. A report by University of Phoenix indicated that out of a survey of 300 recent business graduates, 75 had jobs. You are a business major at University of Phoenix and have a concern about getting a job. Based on this data, will a graduate of University of Phoenix have a better chance of getting a job in the first 6 months after graduation? Use the .05 significant level for the test.
A. No, there is not a significant difference.
B. It cannot be predicted based on this data.
C. Yes, there is a significant difference.
D. The business journal information is incorrect.
12) Analysis of variance (ANOVA) is used to
A. compare nominal data
B. compute t- test
C. compare population proportion
D. simultaneously compare several population means
13) Mr. Thomas owns three different restaurants in Cincinnati, Ohio. He is concerned about the profitability of the restaurants. There are monthly differences between the restaurants and he wants to determine if the differences in profit are significant. Mr. Thomas wants to do a statistical test to see if he should be concerned. The best test to address this problem would be
A. a paired t- test
B. two different t tests
C. an ANOVA test
D. a two sample test
14) Sound engineers studied factors that might affect the output, in decibels, of a rock concert's speaker system. The desired level of significance was a = .05. The results of their ANOVA tests are shown:
Source of Variation SS df MS F P-value
Amplifier 99.02344 99.02344 0.005718
Position 93.98698 31.32899 3.215807 0.051003
Interaction 10.15365 3 3.384549 0.347412 0.791505
Error 155.875 16 9.742188
Total 359.0391 23
The interaction between the Position and Amplifier treatments was
A. very significant
B. slightly significant
D. highly correlated
15) Totto, an automobile manufacturer, has designed a radically new engine and wants to recommend the grade of gasoline that will have the best fuel economy. The four grades are regular, below regular, premium, and super premium. The test car made three trial runs on the test track using each of the grades and the miles per gallon were recorded. At the 0.05 level, what is the critical value of F used to test the hypothesis that the miles per gallon for each fuel are the same?
16) If an ANOVA test is conducted and the null hypothesis is rejected, what does this indicate?
A. Too many degrees of freedom
B. A difference between at least one pair of population means
C. No difference between the population means
D. The variances are the same
17) Nonparametric statistics are used when
A. you have qualitative data, with your variables being measured at the nominal or interval level
B. you have qualitative data, with your variables being measured at the ordinal or ratio level
C. you have qualitative data, with your variables being measured at the nominal or ordinal level
D. you have qualitative data, with your variables being measured at the ordinal or interval level
18) The nonparametric test most commonly used for testing the statistical independence between two variables is
A. the Kruskal- Wallis test
B. the Chi- Square test
C. the Mann Whitney test
D. the Sign test
19) What nonparametric test is used when the assumptions for the parametric ANOVA cannot be met? Its purpose is to test whether three or more populations are equal. The data must be at least ordinal scaled.
A. Students' t
B. Kruskal- Wallis
the critical z-values for a two-tailed hypothesis test if the significant level = 0.01?