Statistics A Tool for Social Research International Edition 9th Edition by Joseph F. Healey - Test Bank

Statistics A Tool for Social Research International Edition 9th Edition by Joseph F. Healey – Test Bank

 

Instant Download – Complete Test Bank With Answers

 

 

Sample Questions Are Posted Below

 

Chapter 5      

THE NORMAL CURVE

 

Multiple Choice Questions

 

1. A defining characteristic of the normal curve is that it is                        a. theoretical
2. positively skewed
3. negatively skewed
4. perfectly nonsymmetrical

Answer: a                     Page: 118                                 LO: 1

 

2. By definition, the normal curve is
3. symmetrical
4. positively skewed
5. negatively skewed
6. empirical

Answer: a                     Page: 118                                 LO: 1

 

3. The tails of the theoretical normal curve
4. intersect with the horizontal axis between the 4th and 5th standard deviation
5. intersect with the horizontal axis beyond the 5th standard deviation
6. never touch the horizontal axis
7. maintain the same distance above the horizontal axis beyond the 3rd standard deviation

Answer: c                     Page: 118                                 LO: 1

 

4. Unlike empirical distribution, the theoretical normal curve is
5. positively skewed
6. negatively skewed
7. bimodal
8. perfectly symmetrical

Answer: d                     Page: 118                                 LO: 1

 

5. On all normal curves the area between the mean and ± 1 standard deviation will be
6. about 34% of the total area
7. about 68% of the total area
8. 50% of the total area
9. 99.9% of the total area

Answer:  b                   Page: 120                                 LO: 1

 

6. On all normal curves the area between the mean and ± 2 standard deviations will be
7. about 34% of the total area
8. about 95% of the total area
9. less than 50% of the total area
10. about 68% of the total area

Answer: b                     Page: 120                                 LO: 1

 

7. On all normal curves the area between the mean and +1 standard deviation will be
8. about 34% of the total area
9. about 68% of the total area
10. about 95% of the total area
11. about 99% of the total area

Answer: a                     Page: 120                                 LO: 1

 

8. Assuming a normal distribution of 1000 cases, how many cases will be farther away from the mean than + 3 standard deviations?
9. at least 500
10. about 3
11. 327
12. it’s impossible to estimate

Answer: b                    Page: 121                                 LO: 2

 

9. Assuming a normal distribution of 1000 cases, how many cases will be within ± 1 standard deviations of the mean?
10. at least 500
11. about 3
12. about 680
13. it’s impossible to estimate

Answer: c                     Page: 121                                 LO: 2

 

10. As the standard deviation of a normal distribution increases, the percentage of the area between ± 1 standard deviation will
11. increase
12. stay the same
13. decrease
14. become non-symmetrical

Answer: b                     Page: 120                                 LO: 1

 

11. The area beyond ± 2 standard deviations contains approximately what % of the area under the normal curve?
12. 75%
13. 50%
14. 99%
15. 5%

Answer:  d                   Page: 120                                 LO: 2

 

12. Distributions of IQ scores are normally distributed because
13. the underlying quality being tested – intelligence – is normally distributed
14. IQ tests are designed to produce in normal distributions
15. there is no cultural bias in the tests
16. they reflect the natural distribution of intelligence: human beings are genetically programmed to have an average intelligence of about 100.

Answer:  b                   Page: 121                                 LO: 1

 

13. Converting scores into Z scores standardizes the original distribution to units of the a.   median
14. standard deviation
15. mean
16. percentage

Answer: b                    Page: 122                                 LO: 2

 

14. A Z score of +1.00 indicates a score that lies
15. one standard deviation unit to the right of the mean
16. one standard deviation unit to the left of the mean
17. 1/2 of one standard deviation unit on each side of the mean
18. any of the above are possible

Answer: a                     Page: 122                                 LO: 2

 

15. A Z score of -2.00 indicates a score that lies
16. two standard deviation units to the right of the mean
17. two standard deviation units to the left of the mean
18. 0.5 of one standard deviation unit on each side of the mean
19. any of the above are possible depending on the value of the mean

Answer: b                    Page: 122                                 LO: 2

 

16. The standardized normal distribution (or Z distribution) has
17. a mean of 0 and a standard deviation of 1
18. a mean of 1 and a standard deviation of 0
19. a mean equal to the average of the scores and a standard deviation equal to the mean
20. a mean of 1 and a standard deviation of 1

Answer: a               Page: 122                                 LO: 2

 

17. When an empirical normal distribution of scores is standardized
18. the mean will become 0
19. the standard deviation will become 1
20. each score will be converted to a Z score
21. all of the above

Answer: d                    Page: 122                                 LO: 2

 

18. If a Z score is 0, then the value of the corresponding raw score would be
19. 0
20. the same as the mean of the empirical distribution
21. the same as the standard deviation of the empirical distribution
22. probably a negative number

Answer: b                    Page:    122                  LO: 2

 

19. If a Z score is + 1.00, then the value of the corresponding raw score would be
20. 0
21. the same as the mean of the empirical distribution
22. equal to the mean of the empirical distribution plus one standard deviation
23. probably a negative number

Answer: c                     Page: 122                                 LO: 2

 

20. The Z score table gives the area between a score and the mean. For a Z score of -1.00 that area (in percentages) is
21. 34.13%
22. -34.13%
23. 68.26%
24. -68.26%

Answer: a                     Page: 122                     LO: 2

 

21. Column c in the normal curve table lists “areas beyond Z”. This is the area
22. below a positive Z score
23. above a negative Z score
24. between two positive Z scores
25. above a positive Z score

Answer: d              Page: 121                                 LO: 22

 

22. The area between the mean and a Z score of +1.50 is 43.32%. This score is higher than _________ of the scores in the distribution.
23. 43.32%
24. 51.50%
25. 57.68%
26. 93.32%

Answer: d                    Page: 122-124                          LO: 2

 

23. The area between the mean and a Z score of +1.50 is 43.32%. This score is less than _________ of the scores in the distribution.
24. 43.32%
25. 6.68%
26. 3.32%
27. 93.32%

Answer: b                    Page: 122-124                          LO: 2

 

24. The mean score on a final chemistry exam was 75, and the standard deviation of the scores was 5. If the distribution is normal and your score was 70, what percentage of the scores was lower than yours?
25. 15.87%
26. 30.00%
27. 34.13%
28. 50.00%

Answer: a                     Page: 122-124                          LO: 2

 

25. The mean on a standardized test is 100 and the standard deviation is 35. Your score is 65. What percentage of the scores were higher than yours?
26. about 84%
27. no more than 50%
28. about 34%
29. about 16%

Answer: a                     Page: 122-124                          LO: 2

 

26. To find the area above a positive Z score or below a negative Z score you would
27. subtract the value of the Z score from the mean
28. use the “Area Beyond Z” column of the Z score table
29. add the value of the Z score to the area beyond the mean
30. add the area between the Z score and the mean to 100%

Answer: b                    Page: 124-126                          LO: 2

 

27. To obtain the area below a positive Z score or above a negative Z score you would
28. subtract the value of the Z score from the mean
29. subtract the area in the “Area Beyond Z” column of the Z score table from 50%
30. add the value of the Z score to the area beyond the mean
31. add the area between the Z score and the mean to 50%

Answer: d                    Page: 124-126                          LO: 2

 

28. The Z scores of two tests scores are + 1.2 and + 1.5. To obtain the area between these scores
29. subtract the Z scores and find the area of the difference in the Z score table
30. find the area between each score and the mean in the Z score table and then subtract the smaller area from the larger area
31. find the area between each score and the mean in the Z score table and then subtract the

difference between them from 100%

1. find the area beyond each score in the Z score table and subtract the difference between the areas from the mean

Answer: b                    Page: 127-129                          LO: 2

 

29. The area between a negative Z score and a positive Z score can be found by
30. subtracting the Z scores from each other
31. subtracting each Z score from the mean and adding the results
32. adding the Z scores and finding the area in the Z score table for the summed Z scores
33. adding the areas between each Z score and the mean

Answer: d                    Page: 127-129                          LO: 2

 

30. The Z scores of two test scores are – 1.17 and + 2.38. To find the total area between these two scores
31. add the column b areas together
32. subtract each score from the mean and divide the result by the standard deviation
33. add the column b area to the column c area
34. add the column c areas

Answer: d                    Page: 127-129                          LO: 2

 

31. The area between two negative Z scores can be found by
32. adding the Z scores and finding the area below the total Z score
33. subtracting the Z scores and finding the total area above the total Z score
34. finding the area between each Z score and the mean and subtracting the smaller area from the larger
35. finding the area between each Z score and the mean and adding the areas

Answer: c                     Page: 127-129              LO: 2

 

32. To estimate probabilities, set up a fraction with the number of _________ in the numerator and the number of _________ in the denominator
33. successes, failures
34. possible outcomes, successes
35. failures, successes
36. successes, possible outcomes

Answer: d                     Page: 130                     LO: 3

 

33. The probability of getting a 1 in a single toss of a six sided die would be            a.  2 to 1
34. 60 to 1
35. 1 in 6
36. impossible to estimate with the information given

Answer: c                     Page: 130                                 LO: 3

 

34. As used in the social sciences, probabilities are a type of ___________ which can vary from _____________ .
35. percentage, 0 to 1
36. fraction, 0 to 100
37. proportion, 0.00 to 1.00
38. Z score, 0 to infinity

Answer: c                     Page: 130                     LO: 3

 

35. If a case is randomly selected from a normal distribution, the score of the case will most likely be
36. equal to the mean in value
37. close to the mean in value
38. at least 1 standard deviation above the mean
39. at least 1 standard deviation below the mean

Answer: b                    Page: 131                                 LO: 3

 

36. The probability that a randomly selected case will have a score beyond ± 1.00 standard deviation of the mean is
37. 0.6826
38. 0.5000
39. 0.3174
40. 1/2 of the area of 1 standard deviation

Answer: c                     Page: 131                                 LO: 3

 

37. A social researcher has constructed a measure of racial prejudice and obtained a distribution of scores on this measure from a randomly selected sample of public office holders. The scores were normally distributed with a mean of 45 and a standard deviation of 7.  What is the probability that a randomly selected case from the sample will have a score less than 38?
38. 0.4526
39. 0.5018
40. 0.5200
41. 0.1587

Answer: d                    Page: 132                                 LO: 3

 

38. What is the probability that a randomly selected case from the sample in the previous question would have a score of 52 or more?
39. 0.7500
40. 0.6826
41. 0.3413
42. 0.1587

Answer: d                    Page:    132                  LO: 3

 

39. What is the probability that a randomly selected case from a normally distributed distribution will have a score between -1.00 and the mean?
40. 0.34
41. 0.16
42. 0.50
43. 0.86

Answer: a                     Page: 132                                 LO: 3

 

40. The average homicide rate for the cities and towns in a state is 10 per 100,000 population with a standard deviation of 2. If the variable is normally distributed, what is the probability that a randomly selected town will have a homicide rate greater than 14?
41. 0.34
42. 0.68
43. 0.50
44. 0.02

Answer: d                    Page: 132                                 LO: 3

 

41. The average homicide rate for the cities and towns in a state is 10 per 100,000 population with a standard deviation of 2. If the variable is normally distributed, what is the probability that a randomly selected town will have a homicide rate greater than 8?
42. 0.34
43. 0.68
44. 0.84
45. 0.01

Answer: c                     Page: 132                                 LO: 3

 

42. The text discusses an application of probability theory that involved
43. betting on horse races
44. casino gambling
45. cheating on final exams
46. betting on the outcome of the presidential election

Answer: b                    Page: 132                                 LO: 3

 

 

 

 

Problems

 

1. A sample of university students has an average GPA of 2.78 with a standard deviation of 0.45. If GPA is normally distributed, what percentage of the students has GPAs

 

		Z score	Area
a.	less than 2.30
b.	less than 2.00
c.	more than 2.00
d.	more than 3.00
e.	between 2.50 and 3.50
f.	between 2.00 and 2.50

 

 

2. For the distribution of GPAs described in problem 1, what is the probability that a randomly selected student will have a GPA

 

 

		Z score	Probability
a.	less than 3.40
b.	less than 3.78
c.	more than 3.50
d.	more than 2.50
e.	between 2.00 and 3.00
f.	between 3.00 and 3.50

 

 

 

Answers to Problems

 

 

	Z score	Area
a. -1.07 14.23%
b. -1.73 4.18%
c. -1.73 95.82%
d. 0.49 31.21%
e. -0.62 and 1.60 67.76%
f. -1.73 and -0.62 22.58%

 

	Z score	Area
a.	1.38	0.92
b.	2.22	0.99
c.	1.60	0.06
d.	-0.62	0.73
e.	-1.73 and 0.49	0.65
f.	0.49 and 1.60	0.26