Statistics and Data Analysis for Nursing Research 2nd Edition By Denise F. Polit – Test Bank

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Chapter 5

Statistical Inference 

5.1. Probabilities are traditionally shown as values ranging from ____ to ____. (Fill in the blanks.)

a. -1.00, +1.00

*b. .00, 1.00

c. 0.0, 100.0

d. -100.0, +100.0

5.2. On a 36-slot roulette wheel (that is, excluding values for “0” or “00”), what is the probability of a roulette spin yielding an even number?

a. .028

b. .25

*c. .50

d. 1.00

5.3. What does the symbol H₀ represent? 

a. A directional hypothesis

b. A nondirectional hypothesis

c. A research hypothesis

*d. A null hypothesis

5.4. Descriptive statistics are rarely exactly equal to population parameters because of: 

*a.  Sampling error

b. Attrition bias

c. Type I errors

d. Type II errors

5.5. A sampling distribution of the mean is a distribution of: 

a. Population values from an entire population

b. Sample values from a random sample

*c. Sample means from an infinite number of samples of a given size

d. Sample values from a sample of samples of a given size

5.6. In a sampling distribution of the mean, which of the following is true? 

a. The mean is equal to 0.0.

*b. The mean is equal to the population mean.

c. The distribution is a t distribution.

d. The distribution is a binomial distribution.

5.7. The statistic referred to as the SEM is:  

a. The standard deviation of population values

*b. The standard deviation of a sampling distribution of means

c. The standard error of measurement

d. The standard estimate of the mean

5.8. The formula for estimating the SEM involves which two components?  

a. The mean and SD from a sample

b. The mean and SD from the population

c. The SD from a sample and number of cases in the population 

*d. The SD from a sample and number of cases from that sample 

5.9. Given a mean of 50.0 and an SD of 10.0, which of the following would have the smallest estimated SEM? 

a. A sample size of 50

b. A sample size of 250

*c. A sample size of 500

d. It cannot be determined without knowing the size of the population.

5.10. Because of an interest in precision, researchers prefer: 

*a. Small SEMs

b. Large SEMs

c. A true SEM rather than an estimated SEM

d. An SEM based on population rather then sample values

5.11. Which of the following statements is true? 

a. Parameter estimation is more frequently used by nurse researchers than hypothesis testing.

b. Point estimation is preferred to interval estimation.

*c. Interval estimation involves constructing a confidence interval around a point estimate of a parameter.

d. Estimation procedures are appropriate for estimating population means but not percentages.

5.12. Which of the following would be an element in the formula for computing confidence limits around a sample mean?

a. The 95% CI

*b. A value from the t distribution for a specified sample size

c. The value of 1.96, corresponding to z

d. The sample SD

5.13. In the expression, M = 10.0, 95% CI = 8.0, 12.0, which of the following is true? 

a. There is a 5% probability that the population mean is greater than 12.0.

*b. There is a 2 ½% probability that the population mean is greater than 12.0.

c. 95% of all population means are between 8.0 and 12.0.

d. The population mean has a 95% probability of being 10.0.

5.14. The appropriate theoretical distribution for constructing confidence intervals around an odds ratio is:  

a. A sampling distribution of the mean 

b. A normal distribution 

c. A t distribution 

*d. A binomial distribution 

5.15. Which of the following is true regarding a 95% CI around a proportion? 

a. If the actual proportion is .00, the lower limit of the CI is a negative value.

b. The theoretical distribution is more skewed when the proportion is .50 than when it is .10. 

*c. The closer the proportion is to .50, the wider the CI. 

d. The larger the sample size, the wider the CI.

5.16. In hypothesis testing, which of the following is true? 

*a. The null hypothesis is assumed to be true.

b. Researchers seek to reject the null hypothesis with 100% certainty.

c. p = 1.0 that a true null will be rejected or that a false null will be accepted.

d. The null hypothesis is the same as the research hypothesis.

5.17. A Type I error: 

a. Is the inverse of power

b. Means that the researcher has come to a false-negative conclusion

c. Only occurs when the test is two tailed

*d. Has a risk of occurrence that is under the researchers’ control by designating α

5.18. The level of significance (significance criterion) of a statistical test:  

a. Is the power of the test to reject the null when it is false 

*b. Is a probability level, typically .05 

c. Is a probability level, typically .95

d. Is automatically computed when tests are performed by computer

5.19. The probability of committing a Type II error: 

*a. Is greater when α is .01 than when α is .05

b. Is always greater than the probability of committing a Type I error

c. Is equivalent to 1 – α

d. Is under the control of researchers by establishing a level for β

5.20. In a one-sample t-test: 

a. A sample mean for one group is tested against a sample mean for another group

b. A sample mean is tested against the value of 50.0

*c. A sample mean is tested against a hypothesized value for the population mean

d. A sample mean is tested against the population parameter 

5.21. When a result is statistically significant, this means that: 

*a. The result has a low probability of being due to chance factors 

b. The result is true

c. The result is clinically important 

d. The result will be replicated in other similar studies

5.22. In a one-sample t-test, if the obtained t = -3.21 and the tabled t = 2.01 for α = .05, this means:

a. The null hypothesis is wrong

b. The null hypothesis is right

c. The null hypothesis can be accepted

*d. The null hypothesis can be rejected

5.23. Which of the following two terms belong together? 

a. Null hypothesis, one-tailed test 

*b. Directional hypothesis, one-tailed test

c. Null hypothesis, two-tailed test

d. Directional hypothesis, two-tailed test 

5.24. Which of the following is an assumption of a parametric test?

a. The central limit theorem is applicable.

b. The population values follow a t distribution.

*c. The sample was randomly selected from the population.

d. The risk of a Type I error is .05.

5.25. Nonparametric tests are more likely to be appropriate than parametric tests when: 

*a. The dependent variable is severely skewed

b. The dependent variable is measured on at least an interval scale

c. The sample size is large

d. Values in the population are normally distributed

5.26. A within-subjects test would be required in a study in which: 

*a. Outcomes for a group are compared before and after an intervention 

b. Men are compared to women

c. Lung cancer patients are compared to colon cancer patients

d. Older participants are compared to younger ones

5.27. In a one-sample t-test for a study involving 200 study participants, df would equal: 

a. .05

b. 1

*c. 199

d. 200 % t

5.28. If a statistical test yields a p = .004, this means that:    

a. The probability is 4 in 100 that the research hypothesis is true

b. The probability is 4 in 1,000 that the research hypothesis is true

c. The probability is 4 in 100 that the null hypothesis is true

*d. The probability is 4 in 1,000 that the null hypothesis is true

Questions 5.29 through 5.32 pertain to the following table (Table 5), which presents fictitious results regarding factors associated with delayed extubation after cardiac surgery:

Table 5

Odds Ratios for Late Extubation^a after Cardiac Surgery, by Patient Characteristics (N = 673)

^aLate extubation = More than 5 hours of mechanical ventilation

5.29. Refer to Table 5. Which of the following numbers is a point estimate for a risk index for delayed extubation? 

a. 19.2

b. 29.8

*c. 1.66

d. 1.14

5.30. Refer to Table 5. Which patient characteristic was most associated with a higher risk of delayed extubation?  

a. Sex

b. Race

c. Hypertensive status

*d. Prior experience with CABG

5.31. Refer to Table 5. What is the probability that the OR for delayed extubation for women is less than 1.14? 

*a. .025

b. .05

c. .50

d. .95

5.32. Refer to Table 5. Which patient characteristic was not associated with a significantly higher risk of delayed extubation? 

a. Sex

*b. Race

c. Hypertensive status

d. Prior experience with CABG