Ch.18 Test Bank Hypothesis Testing Means and Proportions

Test Bank

Chapter 18 Hypothesis Testing: Means and Proportions

True-False

1. The p-value can be defined as the largest significance level at

which we would accept the null hypothesis.

2. In a hypothesis test when alpha is pre-specified, the researcher is

trying to determine "Is the probability of what has been observed

lesser than alpha?" and then decide accordingly.

3. The greater the p-value, the higher is the researcher's confidence

in the research findings.

4. The p-value is independent of the sample size.

5. In an ANOVA test, "between-treatment variance" corresponds to the

variance in the response variable for different treatments.

6. In an ANOVA test, "within-treatment variance" corresponds to the

variance in the response variable for a given treatment.

7. In an ANOVA test, if the "between-treatment variance" is lesser than

the "within-treatment variance," then the null hypothesis can be rejected.

8. A good descriptive statistic of measuring the strength of

association is to measure "Rho," which is the proportion of variance

accounted for in the sample data.

9. The ANOVA table is a conventional way to present a hypothesis test regarding

the difference between several means.

10. The p‐value generally is sensitive to sample size, in that if the sample size

increases, the p‐value usually will become larger.

11. When the sample statistic falls within the critical values, it proves that the null hypothesis

is true.

12. In one-way ANOVA, we primarily look to determine whether or not there are any

statistically significant differences between the treatment means

13. An interaction effect means that the impact of a specific treatment will not be the same for

each condition of the other treatment in the ANOVA analysis.

Multiple Choice

Use the following information to answer questions 1 - 3

Source of variation Sum of squares Degrees of freedom

Explained ? ?

Unexplained ? 32

Total 800 ?

Rho = .20 and there were 9 groups

1. What was the unexplained variation in this study?
2. 80
3. 160
4. 340
5. 640
6. What is the degrees of freedom for the explained variation?
7. 1
8. 8
9. 9
10. none of the above
11. Assume your answer to 1 was 400 and your answer to 2 was 8, what would

be the F-value for this data?

1. 0.4
2. 1.0
3. 2.5
4. 4.0
5. To measure the difference between means or the difference between independent

sample proportions, one would probably use which statistical technique?

1. chi-square test
2. sign test
3. F-test
4. t-test
5. Which of the following is an underlying assumption for the ANOVA model?
6. The error effects are not normally distributed
7. The mean of the error effects is greater than zero
8. The variance of the error effects is a constant
9. The error effects are correlated

Use the following data collected in an experiment for questions 6 - 10.

Source of variation Degrees of Freedom Sum of Squares

Explained 6 900

Unexplained 13 1225

Total 19 2125

6. How many subjects participated in this experiment?

1. 16
2. 17
3. 18
4. 19

7. What is the value of rho from these data?

1. 0.25
2. 0.333
3. 0.42
4. 0.5

8. What F-value do you find from this table?

1. 0.75
2. 0.9
3. 1.0
4. 1.6

9. If the F-value from this table was .19 and the table value from the back of the

book was 3.89, you would

1. accept the null hypothesis of independence
2. reject the null hypothesis of independence
3. accept the null hypothesis that the explained variance = 0
4. reject the null hypothesis that the explained variance = 0

10. The F-value you would look up in the back of the book would be found with

degrees of freedom F ____, _____.

1. 2, 12
2. 2, 14
3. 12, 2
4. 14, 2

11. The rejection rule is

a. reject the null hypothesis in favor of the alternative hypothesis

b. fail to reject the null and conclude that the product meets specifications.

c. inadequate sample size and hence conduct a retest.

d. standard deviation of the sample to be calculated.

Use the following information for questions 12 through 14.

Jack Enterprises Inc. is a laser printer manufacturer. The board of Jack Enterprises wants to see a perceptible improvement in the quality of the laser printers and specify a defect free production rate of 0.95. The quality assurance manager incorporates some

changes in the assembling process and checks a random sample of 225 printers. She finds that only 87% of the printers are defect free. She wants to test the hypothesis that 95% of the printers manufactured by the company are defect free. The significance level

has been specified at 0.05.

12. The hypothesized value of the defect free printers is

a. 0.87

b. 0.13

c. 0.95

d. none of the above.

13. Standard error of the proportions is

a. 0.0145

b. 0.02

c. -0.0145

d. 0.308

14. The limits of the acceptance region are

a. (.922, 0.978)

b. (.94, 0.97)

c. (.86, 0.91)

d. (.93, 0.98)

15. There are ______ degrees of freedom associated with a sample variance

1. n
2. n-1
3. n-2
4. n₁- + n₂ - 2

16. A 95% confidence interval means

a) a researcher is 95% sure of the study results

b) respondents are confident, on the average, of 95% of the answers they give

c) chi-square tests are equal to .95

d) 95 out of 100 samples taken from that universe would give results in the interval

17. The choice of a distribution depends on:

a) the purpose of the hypothesis testing

b) size of the sample

c) whether or not the population standard deviation is known

d) all of the above