Homework answers / question archive / 1)Statistical measures used to yield information about the center or the middle parts of a group of numbers are called the measures of central tendency

1)Statistical measures used to yield information about the center or the middle parts of a group of numbers are called the measures of central tendency

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1)Statistical measures used to yield information about the center or the middle parts of a group of numbers are called the measures of central tendency.

 

 

 

 

 

2. The most appropriate measure of central tendency for nominal-level data is the median.

 

 

 

 

 

3. The most frequently occurring value in a set of data is called the mode.

 

 

 

 

 

4. An appropriate measure of central tendency for ordinal data is the mode.

 

 

 

 

 

 

 

5. It is inappropriate to use the mean to analyze data that are not at least interval level in measurement.

 

 

 

 

 

 

 

6. The lowest appropriate level of measurement for the median is ordinal.

 

 

 

 

 

 

 

7. The middle value in an ordered array of numbers is called the mode.

 

 

 

 

 

 

 

8. Average deviation is a common measure of the variability of data containing a set of numbers.

 

 

 

 

 

 

 

9.   The sum of deviations about the arithmetic mean is always equal to zero.

 

 

 

 

 

 

 

10. The average of the squared deviations about the arithmetic mean is called the variance.

 

 

 

 

 

 

 

11. The sample standard deviation is calculated by taking the square root of the population standard deviation.

 

 

 

 

 

 

 

12. Skewness and kurtosis of a data set are measures of the shape of the distribution.

 

 

 

 

 

 

 

13. Skewness indicates is a data distribution is symmetrical or asymmetrical.

 

 

 

 

 

 

 

14. Kurtosis is a measure of the association between two numerical variables.

 

 

 

 

 

 

 

15. If the mean of a distribution is greater than the median, then the distribution is positively skewed.

 

 

 

 

 

 

 

16. If the median of a distribution is greater than mean, then the distribution is skewed to the left.

 

 

 

 

 

 

 

17. A box and whisker plot is determined from the mean, the smallest and the largest values, and the lower and upper quartile.

 

 

 

 

 

 

 

Multiple Choice

 

 

 

18. The number of standard deviations that a value (x) is above or below the mean is the _________________.

a) absolute deviation

b) coefficient of variation

c) interquartile range

d) z score

e) correlation coefficient

 

 

 

 

 

 

 

19. The empirical rule says that approximately what percentage of the values would be within 2 standard deviations of the mean in a bell shaped set of data?

a) 95%

b) 68%

c) 50%

d) 97.7%

e) 100%

 

 

 

 

 

 

 

20. The empirical rule says that approximately what percentage of the values would be within 1 standard deviation of the mean in a bell shaped set of data?

a) 95%

b) 68%

c) 50%

d) 97.7%

e) 100%

 

 

 

 

 

 

 

21. According to Chebyshev's Theorem how many values in a data set will be within 2 standard deviations of the mean?

a) At least 75%

b) At least 68%

c) At least 95%

d) At least 89%

e) At least 99%

 

 

 

 

 

 

 

22. According to Chebyshev's Theorem how many values in a data set will be within 3 standard deviations of the mean?

a) At least 75%

b) At least 68%

c) At least 95%

d) At least 89%

e) At least 99%

 

 

 

 

 

 

 

23. A statistics student made the following grades on 5 tests: 84, 78, 88, 78, and 72.  What is the mean grade?

a) 78

b) 80

c) 72

d) 84

e) 88

 

 

 

 

 

 

 

24. A statistics student made the following grades on 5 tests:  84, 78, 88, 72, and 72.  What is the median grade?

a) 88         

b) 72

c) 78

d) 80

e) 82

 

 

 

 

 

 

 

25. A statistics student made the following grades on 5 tests:  84, 78, 88, 78, and 82.   What is the mode?

a) 78

b) 80

c) 88

d) 84

e) 82

 

 

 

 

 

 

 

26. A commuter travels many miles to work each morning.  She has timed this trip 5 times during the last month.  The time (in minutes) required to make this trip was 34, 39, 41, 35, and 41.  The mean time (in minutes) required for this trip was _______.

a) 35

b) 41

c) 37.5

d) 38

e) 35.5

 

 

 

 

 

 

 

27. A commuter travels many miles to work each morning.  She has timed this trip 5 times during the last month.  The time (in minutes) required to make this trip was 34, 39, 41, 35, and 41.  The median time (in minutes) required for this trip was _______.

a) 39

b) 41

c) 37.5

d) 38

e) 35.5

 

 

 

 

 

 

 

28. A commuter travels many miles to work each morning.  She has timed this trip 5 times during the last month.  The time (in minutes) required to make this trip was 34, 39, 41, 35, and 41.  The modal time required for this trip was _______.

a) 39

b) 41

c) 37.5

d) 38

e) 35

 

 

 

 

 

 

 

29. A commuter travels many miles to work each morning.  She has timed this trip 5 times during the last month.  The time (in minutes) required to make this trip was 44, 39, 41, 35, and 41.  The mean time required for this trip was 40 minutes.  What is the variance for this sample data?

a) 8.8

b) 11

c) 0

d) 3

e) -2

 

 

 

 

 

 

 

30. A commuter travels many miles to work each morning.  She has timed this trip 5 times during the last month.  The time (in minutes) required to make this trip was 44, 39, 41, 35, and 41.  The mean time required for this trip was 40 minutes.  What is the standard deviation for this sample data?

a) 3.32

b) 2.97

c) 1.73

d) 11

e) -1.4

 

 

 

 

 

 

31. A commuter travels many miles to work each morning.  She has timed this trip 5 times during the last month.  The time (in minutes) required to make this trip was 44, 39, 41, 35, and 41.  The mean time required for this trip was 40 minutes.  What is the mean absolute deviation for this sample data?

a) 0

b) 12

c)  3

d) 2.4

e) 1.2

 

 

 

 

 

 

 

32. The mean life of a particular brand of light bulb is 1000 hours and the standard deviation is 50 hours. We can conclude that at least 75% of this brand of bulbs will last between _______.

a) 900 and 1100 hours

b) 950 and 1050 hours

c) 850 and 1150 hours

d) 800 and 1200 hours

e) 1050 and 1250 hours

 

 

 

 

 

 

 

33. The mean life of a particular brand of light bulb is 1000 hours and the standard deviation is 50 hours.  It can be concluded that at least 89% of this brand of bulbs will last between _______.

 

a) 900 and 1100 hours

b) 950 and 1050 hours

c) 850 and 1150 hours

d) 800 and 1200 hours

e) 1050 and 1250 hours

 

 

 

 

 

 

 

34. The mean life of a particular brand of light bulb is 1000 hours and the standard deviation is 50 hours.  Tests show that the life of the bulb is approximately normally distributed.  It can be concluded that approximately 68% of the bulbs will last between _______.

a) 900 and 1100 hours

b) 950 and 1050 hours

c) 850 and 1150 hours

d) 800 and 1200 hours

e) 1050 and 1250 hours

 

 

 

 

 

 

 

35. Jessica Salas, president of Salas Products, is reviewing the warranty policy for her company's new model of automobile batteries.  Life tests performed on a sample of 100 batteries indicated:  (1) an average life of 75 months, (2) a standard deviation of 5 months, and (3) a bell shaped battery life distribution. Approximately 68% of the batteries will last between ________________.

a) 70 and 80 months

b) 60 and 90 months

c) 65 and 85 months

d) 55 and 95 months

e) 60 and 100 months

 

 

 

 

 

 

 

36. Jessica Salas, president of Salas Products, is reviewing the warranty policy for her company's new model of automobile batteries.  Life tests performed on a sample of 100 batteries indicated:  (1) an average life of 75 months, (2) a standard deviation of 5 months, and (3) a bell shaped battery life distribution. Approximately 95% of the batteries will last between ________________.

a) 70 and 80 months

b) 60 and 90 months

c) 65 and 85 months

d) 55 and 95 months

e) 60 and 100 months

 

 

 

 

 

 

 

37. Jessica Salas, president of Salas Products, is reviewing the warranty policy for her company's new model of automobile batteries.  Life tests performed on a sample of 100 batteries indicated:  (1) an average life of 75 months, (2) a standard deviation of 5 months, and (3) a bell shaped battery life distribution. Approximately 99.7% of the batteries will last between ________________.

a) 70 and 80 months

b) 60 and 90 months

c) 65 and 85 months

d) 55 and 95 months

e) 50 and 100 months

 

 

 

 

 

 

 

38. Jessica Salas, president of Salas Products, is reviewing the warranty policy for her company's new model of automobile batteries.  Life tests performed on a sample of 100 batteries indicated:  (1) an average life of 75 months, (2) a standard deviation of 5 months, and (3) a bell shaped battery life distribution. What percentage of the batteries will fail within the first 65 months of use?

a) 0.5%

b) 1%

c) 2.5%

d) 5%

e) 7.5%

 

 

 

 

 

 

 

39. The average starting salary for graduates at a university is $25,000 with a standard deviation of $2,000.  If a histogram of the data shows that it takes on a mound shape, the empirical rule says that approximately 95% of the graduates would have a starting salary between _______.

a) 23,000 and 27,000

b) 21,000 and 29,000

c) 19,000 and 31,000

d) 24,000 and 26,000

e) 26,000 and 28,000

 

 

 

 

 

 

 

40. The average starting salary for graduates at a university is $25,000 with a standard deviation of $2,000.  If a histogram of the data shows that it takes on a mound shape, the empirical rule says that approximately 68% of the graduates would have a starting salary between _______.

a) 23,000 and 27,000

b) 21,000 and 29,000

c) 19,000 and 31,000

d) 24,000 and 26,000

e) 26,000 and 28,000

 

 

 

 

 

 

 

41. The ages of students in a class have been put into the frequency distribution below.

                                    Age     Number of Students

                                    18                    3

                                    19                    5

                                    20                    28

                                    21                    4

What is the average age of these students?

a) 19.50

b) 19.83

c) 20.00

d) 22.00

e) 23.00

 

 

 

 

 

 

42. The ages of students in a class have been put into the frequency distribution below.

                                    Age     Number of Students

                                    18                    3

                                    19                    5

                                    20                    28

                                    21                    4

What is the standard deviation for this (population) set of data?

a) 0.494

b) 0.703

c) 1.12

d) 1.25

e) 1.35

 

 

 

 

 

43. The ages of students in a class have been put into the frequency distribution below.

                                    Age     Number of Students

                                    18                    3

                                    19                    5

                                    20                    28

                                    21                    4

What is the median age of these students?

a) 18

b) 19

c) 19.5

d) 20

e) 20.5

 

 

 

 

 

 

44. The ages of students in a class have been put into the frequency distribution below.

                                    Age     Number of Students

                                    18                    3

                                    19                    5

                                    20                    28

                                    21                    4

What is the modal age of these students?

a) 18

b) 19

c) 20

d) 21

e) 23

 

 

 

 

 

 

45. An instructor is evaluating the performance of students on a test.  He records the number of points that each student missed and created a frequency distribution.  This is provided below:

                                     Points missed                       Number of students

                                     0-under 10                              2

                                    10-under 20                             4

                                    20-under 30                             10

                                    30-under 40                             8

                                    40-under 50                             6

What is the mean number of points missed?

a) 20

b) 25

c) 29

d) 30

e) 35

 

 

 

 

 

 

46. An instructor is evaluating the performance of students on a test.  He records the number of points that each student missed and created a frequency distribution.  This is provided below:

                                     Points missed                       Number of students

                                     0-under 10                              2

                                    10-under 20                             4

                                    20-under 30                             10

                                    30-under 40                             8

                                    40-under 50                             6

What is the variance for this population?

a) 11.43

b) 135.17

c) 130.67

d) 180.67

e) 198.07

 

 

 

 

 

 

47. An instructor is evaluating the performance of students on a test.  He records the number of points that each student missed and created a frequency distribution.  This is provided below:

                                     Points missed                       Number of students

                                     0-under 10                              2

                                    10-under 20                             4

                                    20-under 30                             10

                                    30-under 40                             8

                                    40-under 50                             6

What is the standard deviation for this population?

a) 11.43

b) 14.14

c) 12.63

d) 13.17

e) 16.90

 

 

 

 

 

 

48. Pinky Bauer, Chief Financial Officer of Harrison Haulers, Inc., suspects irregularities in the payroll system, and orders an inspection of "each and every payroll voucher issued since January 1, 1993."  Each payroll voucher was inspected and the following frequency distribution was compiled.

                                    Errors per Voucher                  Number of Vouchers

                                           0-under 2                                       500

                                           2-under 4                                       400

                                           4-under 6                                       300

                                           6-under 8                                       200

                                         8-under 10                                       100

The mean number of errors per voucher is __________.

a) 3.67

b) 5

c) 750

d) 300

e) 8.7

 

 

 

 

 

 

 

49. Liz Chapa manages a portfolio of 250 common stocks.  Her staff compiled the following performance statistics for two new stocks.

	Rate of Return
Stock	Mean	Standard Deviation
Salas Products, Inc.	15%	5%
Hot Boards, Inc.	20%	5%

The coefficient of variation for Salas Products, Inc. is __________.

a) 300%

b) 100%

c) 33%

d) 5%

e) 23%

 

 

 

 

 

 

 

50. The following box and whisker plot was constructed for the age of accounts receivable.

                       

The box and whisker plot reveals that the accounts receivable ages are _______.

a) skewed to the left

b) skewed to the right

c) not skewed

d) normally distributed

e) symmetrical

 

 

 

 

 

 

 

51. The following box and whisker plot was constructed for the age of accounts receivable.

 

                       

The box and whisker plot reveals that the accounts receivable ages are _______.

a) skewed to the left

b) skewed to the right

c) not skewed

d) normally distributed

e) symmetrical

 

 

 

 

 

 

 

52. The following frequency distribution was constructed for the age of accounts receivable.

 

                                   

The frequency distribution reveals that the accounts receivable ages are _______.

a) skewed to the left

b) skewed to the right

c) not skewed

d) normally distributed

e) symmetrical

 

 

 

 

 

 

 

53. The following frequency distribution was constructed for the age of accounts receivable.

 

                       

The frequency distribution reveals that the accounts receivable ages are _______.

a) skewed to the left

b) skewed to the right

c) not skewed

d) normally distributed

e) symmetrical

 

 

 

 

 

 

 

54. David Desreumaux, VP of Human Resources of American First Banks (AFB), is reviewing the employee training programs of AFB banks.  His staff compiled the following table of regional statistics on teller training hours.

	Southeast Region	Southwest Region
Mean	20	28
Median	20	20
Mode	20	21
Standard Deviation	5	7

What can David conclude from these statistics?

a) The Southeast distribution is skewed to the left.

b) The Southeast distribution is skewed to the right.

c) The Southwest distribution is skewed to the left.

d) The Southwest distribution is skewed to the right.

e) Both distributions are symmetrical.

 

 

 

 

 

 

 

55. David Desreumaux, VP of Human Resources of American First Banks (AFB), is reviewing the employee training programs of AFB banks.  His staff compiled the following table of regional statistics on teller training hours.

	Southeast Region	Southwest Region
Mean	20	28
Median	20	20
Mode	20	21
Standard Deviation	5	7

What can David conclude from these statistics?

a) The Southeast distribution is symmetrical.

b) The Southwest distribution is skewed to the left.

c) The Southeast distribution has the greater dispersion.

d) The Southeast distribution is skewed to the left.

e) The two distributions are symmetrical.

 

 

 

 

 

 

 

56. Manuel Banales, Marketing Director of Plano Power Plants, Inc.’s Electrical Division, is leading a study to assess the relative importance of product features.  Two items on a survey questionnaire distributed to 100 of Plano’s customers asked them to rate the importance of “ease of maintenance” and “efficiency of operation” on a scale of 1 to 10 (with 1 meaning “not important” and 10 meaning “highly important”).  His staff assembled the following statistics on these two items.

	Ease of Maintenance	Efficiency of Operation
Mean	7.5	6.0
Median	8.5	5.5
Mode	9.0	4.5
Standard Deviation	1.5	2.5

What can Manuel conclude from these statistics?

a) The Ease of Maintenance distribution is skewed to the right.

b) The Ease of Maintenance distribution is not skewed.

c) The Efficiency of Operation distribution is skewed to the left.

d) The Efficiency of Operation distribution is positively skewed.

e) Both are symmetrically distributed.

 

 

 

 

 

 

 

57. In its Industry Norms and Key Business Ratios, Dun & Bradstreet reported that Q1, Q2, and Q3 for 2,037 gasoline service stations' sales to inventory ratios were 20.8, 33.4, and 53.8, respectively.  From this we can conclude that ____________.

a) 68% of these service stations had sales to inventory ratios of 20.8 or less

b) 50% of these service stations had sales to inventory ratios of 33.4 or less

c) 50% of these service stations had sales to inventory ratios of 53.8 or more

d) 95% of these service stations had sales to inventory ratios of 20.8 or more

e) 99% of these service stations had sales to inventory ratios of 20.8 or more

 

 

 

 

 

 

 

58. David Desreumaux, VP of Human Resources of American First Banks (AFB), is reviewing the employee training programs of AFB banks.  His staff reports several statistics for teller training hours.  The mean is 20 hours, the standard deviation is 5 hours, the median is 15 hours, and mode is 10 hours. The Pearsonian coefficient of skewness for teller training hours is __________.

a) 6

b) 1

c) 3

d) 4

e) 0