MIND ON STATISTICS 5TH EDITION BY UTTS – TEST BANK

Sections 11.1 – 11.2

Questions 1 to 4: For each study, decide if the two samples are independent samples or paired samples.

1. A group of 50 students each measured the length of their right arm and the length of their left arm. The average right arm lengths were compared to the average left arm lengths.
A. Independent samples
B. Paired samples
KEY: B

2. A study compared the average number of courses taken by a random sample of 100 freshmen at a university with the average number of courses taken by a separate random sample of 50 freshmen at a community college.
A. Independent samples
B. Paired samples
KEY: A

3. A group of 100 students were randomly assigned to receive vitamin C (50 students) or a placebo (50 students). The groups were followed for 2 weeks and the proportions of students with colds were compared.
A. Independent samples
B. Paired samples
KEY: A

4. A group of 50 students had their blood pressures measured before and after watching a movie containing violence. The mean blood pressure before the movie was compared with the mean pressure after the movie.
A. Independent samples
B. Paired samples
KEY: B

5. Which of the following helps determine the standard error for a confidence interval for a mean?
A. The sample size(s).
B. The sample estimate.
C. The true value of the population parameter.
D. The confidence level.
KEY: A

6. The distinction between a sampling distribution and a confidence interval is:
A. A confidence interval gives possible values for a sample statistic when the population parameter is assumed known, while a sampling distribution gives possible values for a population parameter when only a single value of a sample statistic is known.
B. A sampling distribution gives possible values for a sample statistic when the population parameter is assumed known, while a confidence interval gives possible values for a population parameter when only a single value of a sample statistic is known.
C. Sampling distributions exist only for situations involving means, while confidence intervals can be computed for situations involving means and proportions.
D. Confidence intervals exist only for situations involving means, while sampling distributions can be computed for situations involving means and proportions.
KEY: B

7. A randomly selected sample of 100 students had an average grade point average (GPA) of 3.2 with a standard deviation of 0.2. The standard error of the sample mean is
A. 0.020
B. 0.200
C. 1.600
D. 2.000
KEY: B

8. A randomly selected sample of 30 students spent an average amount of $40.00 on a date, with a standard deviation of $5.00. The standard error of the sample mean is
A. 0.063
B. 0.167
C. 0.913
D. 5.000
KEY: C

9. A random sample of 250 third graders scored an average of 3.2 on a standardized reading test. The standard deviation was 0.95. What is the standard error of the sample mean?
A. 0.95
B. 0.202
C. 0.0038
D. 0.060
KEY: D

10. A randomly selected sample of 60 mathematics majors spent an average of $200.00 for textbooks one term, while during the same term, a randomly selected sample of 40 literature majors spent an average of $180.00 for textbooks. The standard deviation for each sample was $20.00. The standard error for the difference between the two sample means is
A. 0.057
B. 4.082
C. 5.744
D. 16.663
KEY: B