Statistics multiple choice

1. Variance is...
A. The average of the squared deviation from the mean.
B. A measure of variability of data values about the mean.
C. A measure of dispersion.
D. All of the above.
F. None of the above.
2. Analysis of variance means...
A. We compute the variances of the variables observed in the study.
B. We partition variances into treatment variability and random variability.
C. We don't continue unless the variance is nonzero.
D. A psychiatrist does analysis of people with variant behavior.
3. You're a marketing executive in a tire company and you want to establish that your tires are better than average. If the national average tire lifetime is 50,000 miles and your tires average 53,000 miles, what is your alternate hypothesis?
A. &#956;=50,000 C. &#956;&#8804;50,000 E. &#956;<50,000
B. &#956;&#8800;50,000 D. &#956;&#8805;50,000 F. &#956;>50,000
4. In question 3, what is the null hypothesis?
A. &#956;=50,000 C. &#956;&#8804;50,000 E. &#956;<50,000
B. &#956;&#8800;50,000 D. &#956;&#8805;50,000 F. &#956;>50,000
5. A high school counselor has administered a standardized test to 742 sophomores and found that the average score was 1,214 points. The nationwide average is 1,289 points. She has been asked to test these hypotheses: H0: &#956;&#8804;1,289 and H1: &#956;>1,289. What should she do?
A. Compute the test statistic and compare it against the critical value of the test statistic.
B. Do nothing because her sample mean is less than the hypothetical mean.
C. Compute the p-value and compare it to the significance level.
D. All of the above.
F. None of the above.
6. You're an auto parts buyer for a major retailer, and two manufacturers offer tires with equal mean lifetime. You suspect ABC TireCo tires have a more uniform lifetime than TreadTastic tires, so you buy and test a sample of 30 tires from each company to test the hypothesis that the two population variances are equal. What test statistic will you use?
A. Z B. t C. F D. &#967;2
7. If you're testing a null hypothesis that &#956; &#8805; 1,092.4, where is the rejection region?
A. Left tail B. Right tail
8. Nonparametric statistics are used when...
A. We don't know the population's parameter values.
B. We don't know the population's statistical distribution.
9. Nonparametric statistics are the tool of choice when we have...
A. Ratio-level and interval-level data.
B. Nominal-level and ordinal-level data.
10. We have mean batting averages for three groups of baseball teams. We want to test whether there's a difference among these teams. The null hypothesis is:
A. &#956;1 = &#956;2 = &#956;3 C. &#956;1 &#8804; &#956;2 &#8804; &#956;3
B. &#956;1 &#8800; &#956;2 &#8800; &#956;3 D. The three means are not all equal.
11. For the situation in question 10, the alternate hypothesis is:
A. &#956;1 = &#956;2 = &#956;3 C. &#956;1 &#8804; &#956;2 &#8804; &#956;3
B. &#956;1 &#8800; &#956;2 &#8800; &#956;3 D. The three means are not all equal.
12. For the situation in questions 10 and 11, the proper test statistic is:
A. Z B. t C. F D. &#967;2
13. Dr. Harder surveyed his students to see how many recommend that their friends take his class. He found that 10 of 17 RES/341 students said "yes", whereas 19 of 20 SCI/350 students said "yes". What test statistic will he use to test the hypothesis that the population proportion in the two groups is the same?
A. Z B. t C. F D. &#967;2
14. How many cells of a 3-cell chi-square table can have expected frequency less than 5?
A. 0 B. 1 C. 2 D. 3
SCI/350 RES/341 RES/342
Students 15 45 30
15. Dr. Harder must plan future teaching load and needs to estimate how many students will enroll in each course he teaches. He will assume that the proportions of his students who will enroll in each class is equal, unless he finds significant evidence to the contrary. To test the hypothesis, he collects the data shown at right. What is the value of the &#967;2 test statistic?
A. 1.0 B. 5.0 C. 10.0 D. 15.0
16. How many degrees of freedom are there?
A. 1 B. 2 C. 3 D. 4
17. In which step of the hypothesis testing procedure do we compute the critical value or values of the test statistic?
A. Step 1 B. Step 2 C. Step 3 D. Step 4 E. Step 5
18. In which step of the hypothesis testing procedure do we compute the value of the test statistic based on the sample's descriptive statistics?
A. Step 1 B. Step 2 C. Step 3 D. Step 4 E. Step 5
19. In which step of the hypothesis testing procedure do we state the formula for computing the test statistic.
A. Step 1 B. Step 2 C. Step 3 D. Step 4 E. Step 5
20. ANOVA is...
A. A program on educational television.
B. An exploding star.
C. Analysis of variance.
D. A Chevrolet that never sold well in Mexico because "No va" means "Doesn't go".