# Quiz 4: Central Tendency and Variability

Psychology

Q 1Q 1

The concept of central tendency is best described as:
A) the average.
B) how the data are distributed.
C) the physical middle of our data.
D) the value around which the data seem to gather.

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Multiple Choice

D

Q 2Q 2

A marketing specialist for a major department store wants to know how much time people tend to spend in the store so that the audio advertisements will replay on a timed loop, allowing every customer a chance to hear each unique message.What information is this marketing specialist seeking?
A) variability
B) deviation scores
C) central tendency
D) parameter

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Multiple Choice

C

Q 3Q 3

The mean is calculated by:
A) determining the midpoint of the scores in the data set, such that half fall above the mean and half fall below.
B) summing all of the scores in a data set and then dividing by the total number of scores.
C) subtracting the lowest score from the highest score in the data set.
D) determining the most common score in a data set.

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Multiple Choice

B

Q 4Q 4

Six students from a psychology class reported the number of hours of television they watched per week.Here are their data: 18, 12, 15, 14, 13, 16.What is the mean number of hours of television watched per week for this sample of six students?
A) 2.45
B) 6.00
C) 14.50
D) 14.67

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Multiple Choice

Q 5Q 5

Sixteen college freshmen were asked to record the number of alcoholic drinks that they typically consume in a week.Here are their data: 2, 4, 6, 0, 1, 10, 9, 0, 6, 3, 6, 8, 5, 4, 6, 2.What is the mean number of alcoholic drinks consumed per week?
A) 4.50
B) 4.94
C) 5.20
D) 6.00

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Multiple Choice

Q 6Q 6

Here is a set of data: 31, 54, 26, 42, 39, 45, 38, 42.What is the mean?
A) 26.00
B) 28.00
C) 39.63
D) 52.84

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Multiple Choice

Q 7Q 7

Numbers that describe samples are called:
A) statistics.
B) parameters.
C) averages.
D) variables.

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Multiple Choice

Q 8Q 8

Numbers that describe populations are called:
A) statistics.
B) parameters.
C) averages.
D) variables.

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Multiple Choice

Q 9Q 9

The mean of the population is represented by the symbol _____, and the mean of the sample is represented by the symbol _____.
A) M;
B) ; M
C) ;
D) M; M

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Multiple Choice

Q 10Q 10

In a physical geography course, the average score on the first exam was 79 percent based on a sample of 48 students.This mean was calculated on the class grades to summarize overall performance.There are two other sections of the same class, but those students were not included in the calculation.The test average is a:
A) measure of variability.
B) statistic.
C) parameter.
D) mode.

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Multiple Choice

Q 11Q 11

In a physical geography course, the average score on the first exam across all sections of the course was 77.63 percent.Because all students were included in the calculation, the mean is assumed to be based on population data.The test average may be considered to be a:
A) measure of variability.
B) statistic.
C) parameter.
D) mode.

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Multiple Choice

Q 12Q 12

At 24 years of age, Megan is 5 feet, 6 inches tall.The national average for height is 5 feet, 4 inches, so Megan is taller than average.The national average is a:
A) population parameter.
B) standardized measure.
C) sum of squares.
D) sample statistic.

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Multiple Choice

Q 13Q 13

A sample of 150 women results in an average weight calculation of 168 pounds.This average weight is a:
A) population parameter.
B) standardized measure.
C) sum of squares.
D) sample statistic.

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Multiple Choice

Q 14Q 14

The median household income in Albemarle County, Virginia, for the year 2005 was $61,660.If the mean and mode are also computed, which statement could NOT be true?
A) Half of the households had incomes below the median.
B) The majority of households had incomes above the mean.
C) The majority of households had incomes above the median.
D) The majority of households had incomes above the mode.

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Multiple Choice

Q 15Q 15

The median is the number that perfectly balances the:
A) number of scores in the data set, such that half fall above the median and half fall below the median.
B) deviations of the scores from the mean, such that the sum of the deviations for scores above the mean exactly equals the sum of the deviations for scores below the mean.
C) two most extreme scores in the data set.
D) even and the odd scores in the data set.

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Multiple Choice

Q 16Q 16

Six students from a psychology class reported the number of hours of television they watched per week.Here are their data: 18, 12, 15, 14, 13, 16.What is the median number of hours of television watched per week for this sample of six students?
A) 12.0
B) 14.0
C) 14.5
D) 18.0

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Multiple Choice

Q 17Q 17

Sixteen college freshmen were asked to record the number of alcoholic drinks that they typically consume in a week.Here are their data: 2, 4, 6, 0, 1, 10, 9, 0, 6, 3, 6, 8, 5, 4, 6, 2.What is the median number of alcoholic drinks consumed per week?
A) 4.0
B) 4.5
C) 5.0
D) 5.5

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Multiple Choice

Q 18Q 18

Here is a set of data: 31, 54, 26, 42, 39, 45, 38, 42.What is the median?
A) 28.0
B) 40.5
C) 42.0
D) 54.0

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Multiple Choice

Q 19Q 19

When calculating the median for an odd number of scores, which have been placed in ascending order, the median will be the:
A) middle score.
B) difference between the highest and lowest scores.
C) average of the three scores in the middle.
D) average of the two scores in the middle.

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Multiple Choice

Q 20Q 20

Here is a set of data: 31, 54, 26, 42, 39, 45, 38, 42, 47.What is the median?
A) 28.0
B) 40.5
C) 42.0
D) 54.00

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Multiple Choice

Q 21Q 21

The most frequently occurring score in a distribution is the:
A) mean.
B) median.
C) mode.
D) sample statistic.

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Multiple Choice

Q 22Q 22

Sixteen college freshmen were asked to record the number of alcoholic drinks they typically consume in a week.Here are their data: 2, 4, 6, 0, 1, 10, 9, 0, 6, 3, 6, 8, 5, 4, 6, 2.What is the mode of this distribution?
A) 2
B) 4
C) 4.5
D) 6

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Multiple Choice

Q 23Q 23

Here is a set of data: 31, 54, 26, 42, 39, 45, 38, 42.What is the mode?
A) 39.63
B) 40.50
C) 42.00
D) 54.00

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Multiple Choice

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Multiple Choice

Q 27Q 27

Professor Kellogg calculates the grades on the first exam for her statistics class.She finds that students did either really well or really poorly.What kind of distribution does Prof.Kellogg have?
A) normal
B) unimodal
C) bimodal
D) negatively skewed

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Multiple Choice

Q 28Q 28

Katrina observes and records the number of people who purchase a meal at the school cafeteria during each operating hour.The cafeteria is open from 6:00 a.m.to 9:00 p.m.and students typically eat breakfast, lunch, and dinner.What type of distribution should Katrina expect to see in her data?
A) normal
B) unimodal
C) bimodal
D) multimodal

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Multiple Choice

Q 29Q 29

The median is preferred over the mean for _____ distributions.
A) normal
B) unimodal
C) skewed
D) symmetrical

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Multiple Choice

Q 30Q 30

In a sample of data that has several extremely high scores, creating positive skew, the mean:
A) will be less than the mode.
B) will be greater than the median.
C) and the mode will be equal.
D) will be less than the median.

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Multiple Choice

Q 31Q 31

In a sample of data that has several extremely low scores, creating negative skew, the mean:
A) will be greater than the mode.
B) will be greater than the median.
C) and the mode will be equal.
D) will be less than the median.

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Multiple Choice

Q 32Q 32

_____ is affected by outliers because it takes the actual value of each data point into consideration.
A) Mode
B) Median
C) Mean
D) Center

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Multiple Choice

Q 33Q 33

Here is a set of scores: 18, 99, 14, 16, 31, 43, 12, 14, 13, 51, 12.Which score is considered to be an outlier?
A) 12
B) 14
C) 51
D) 99

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Multiple Choice

Q 34Q 34

In a sample of data that has several extremely high scores, creating positive skew, the mean will be _____ the median.
A) less than
B) greater than
C) equal to
D) double

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Multiple Choice

Q 35Q 35

In a sample of data that has several extremely low scores, creating negative skew, the mean will be _____ the median.
A) less than
B) greater than
C) equal to
D) double

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Multiple Choice

Q 36Q 36

In a distribution that is skewed by a few extreme outliers, what would be the best choice for a measure of central tendency?
A) median
B) mode
C) mean
D) range

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Multiple Choice

Q 37Q 37

If you wanted to know whether judges in your state are typically male or female, what measure of central tendency would you use to describe the typical judge?
A) mean
B) median
C) mode
D) range

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Multiple Choice

Q 38Q 38

If you knew nothing about your data except that it is a scale variable, which measure of central tendency would be the "safest bet"?
A) mode
B) median
C) mean
D) center

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Multiple Choice

Q 39Q 39

The concept of variability is best described as:
A) the spread of the distribution of data.
B) the lack of consistency in data values.
C) the average deviation of the data.
D) how data tend to cluster around a center.

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Multiple Choice

Q 40Q 40

Around the end-of-year holidays, such as Thanksgiving, a great amount of meat is purchased.To be prepared for the increased demand, a local grocery store manager wants to know the typical amount of ham sold at medium-sized stores around Thanksgiving.But even more than that, he wants to know how sales tend to vary around that typical amount because he wants to be prepared to sell as many hams as possible.His interest in how much sales vary will require a measure of:
A) central tendency.
B) variability.
C) parameters.
D) statistics.

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Multiple Choice

Q 41Q 41

The _____ is the difference between the lowest and highest scores in the distribution.
A) standard deviation
B) range
C) variance
D) outlier

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Multiple Choice

Q 42Q 42

Sixteen college freshmen were asked to record the number of alcoholic drinks they typically consume in a week.Here are their data: 2, 4, 6, 0, 1, 10, 9, 0, 6, 3, 6, 8, 5, 4, 6, 2.What is the range of this distribution?
A) 0 to 10
B) 2
C) 9
D) 10

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Multiple Choice

Q 43Q 43

Here is a set of data: 31, 54, 26, 42, 39, 45, 38, 42.What is the range?
A) 26
B) 28
C) 42
D) 54

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Multiple Choice

Q 44Q 44

Which set of scores has the least amount of variability?
A) 22, 26, 21, 23
B) 32, 72, 86, 100
C) 5, 18, 62, 78
D) 101, 110, 56, 13

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Multiple Choice

Q 45Q 45

If the variance for a sample is computed and it is found to be rather large, the numbers in the sample are:
A) tightly packed at one extreme.
B) tightly packed around the mean.
C) spread out around the mean.
D) close to the extremes of the distribution.

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Multiple Choice

Q 46Q 46

Sixteen college freshmen were asked to record the number of alcoholic drinks they typically consume in a week.Here are their data: 2, 4, 6, 0, 1, 10, 9, 0, 6, 3, 6, 8, 5, 4, 6, 2.What is the variance of the number of alcoholic drinks consumed per week?
A) 2.96
B) 3.26
C) 8.75
D) 12.25

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Multiple Choice

Q 47Q 47

Six students from a psychology class reported the number of hours of television they watch per week.Here are their data: 18, 12, 15, 14, 13, 16.The variance of the number of hours of television watched per week for this sample of six students is:
A) 1.97.
B) 3.89.
C) 15.13.
D) 23.33.

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Multiple Choice

Q 48Q 48

Here is a set of data: 44, 52, 51, 37, 49, 55, 48, 39.Compute a deviation score for the data point 51.
A) 0
B) 4.13
C) 15.00
D) 46.88

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Multiple Choice

Q 49Q 49

Variance is the average of deviations around the mean expressed in _____ units.
A) standardized
B) absolute value
C) squared
D) logarithmic

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Multiple Choice

Q 50Q 50

Here is a set of data: 44, 52, 51, 37, 49, 55, 48, 39.Compute a deviation score for the data point 44.
A) -4.16
B) -2.88
C) 0.62
D) 1.74

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Multiple Choice

Q 51Q 51

We _____ when calculating the average of deviations from the mean, because the sum of all deviation scores around the mean equals zero.
A) take the absolute value of the scores
B) square the scores
C) divide by N
D) take the square root

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Multiple Choice

Q 52Q 52

If the standard deviation of some data is 4.19, what is the range?
A) 0.93
B) 0.89
C) 0.74
D) It is impossible to determine the range based on the information provided.

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Multiple Choice

Q 53Q 53

A researcher analyzed the results of her data and calculated the standard deviation of scores at 6.7.What is the variance?
A) 2.59
B) 6.70
C) 13.40
D) 44.89

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Multiple Choice

Q 54Q 54

Six students from a psychology class reported the number of hours of television they watch per week.Here are their data: 18, 12, 15, 14, 13, 16.What is the standard deviation of the number of hours of television watched per week for this sample of six students?
A) 1.97
B) 3.89
C) 14.67
D) 23.33

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Multiple Choice

Q 55Q 55

If the standard deviation of some data is 0.347, what is the variance?
A) 0.35
B) 0.12
C) 0.69
D) It is impossible to determine the variance based on the information provided.

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Multiple Choice

Q 56Q 56

A standard deviation is equal to 5.50.This number means that the numbers in the sample deviate, on the average:
A) 2.25 units from the mean.
B) 5.50 units from each other.
C) 5.50 units from the mean.
D) 5.50 units from the two extreme scores.

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Multiple Choice

Q 57Q 57

If an extreme score is added to a data set, increasing the range of data, the standard deviation will:
A) get closer to 0.
B) decrease.
C) increase.
D) double.

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Multiple Choice

Q 58Q 58

A researcher analyzed the results of her data and calculated the variance of scores at 113.00.What is the standard deviation?
A) 10.63
B) 21.26
C) 56.50
D) 113.00

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Multiple Choice

Q 59Q 59

If the variance of some data is 26.84, what is the standard deviation?
A) 5.18
B) 8.95
C) 10.36
D) It is impossible to determine the standard deviation based on the information provided.

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Multiple Choice

Q 60Q 60

The mean is the measure of central tendency that conveys the mathematical center of the data.

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True False

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True False

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True False

Q 63Q 63

The median is the measure of central tendency that conveys the mathematical center of the data.

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True False

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True False

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True False

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True False

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True False

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True False

Q 69Q 69

The range is more susceptible to the influence of outliers than other measures of variability.

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True False

Q 70Q 70

The range is less susceptible to the influence of outliers than other measures of variability.

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True False

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True False

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True False

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True False

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True False

Q 75Q 75

The most common measure of variability reported in research articles is the standard deviation.

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True False

Q 76Q 76

The interquartile range measures variability as the difference between the scores at the 25th and 50th percentiles.

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True False

Q 77Q 77

The interquartile range measures variability as the difference between the scores at the 25th and 100th percentiles.

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True False

Q 78Q 78

The interquartile range measures variability as the difference between the scores at the 75th and 25th percentiles.

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True False

Q 79Q 79

Compared to the interquartile range, the range is less susceptible to the influence of outliers.

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True False

Q 80Q 80

Mark is looking at distance estimates of where participants think cities are located on a map.Since the estimates are given by x, y coordinates, Mark thinks he should use the mode as a measure of central tendency.What other measures of central tendency are also available?
A) median and mean
B) median and outliers
C) range and sum of squares
D) outliers and mean

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Multiple Choice

Q 81Q 81

A graduate business class receives these grades on the final exam: 96, 76, 81, 87, 90, 74, 88, 95, 80, 93.What is the median test score?
A) 84.5
B) 87.0
C) 87.5
D) 88.0

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Multiple Choice

Q 82Q 82

Mark decides to use the mode as the measure of central tendency for his map study.His data set is 3, 17, 22, 5, 4, 16, 27, 22, 17, 22, 5, 3.What is the mode?
A) 5
B) 17
C) 22
D) 27

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Multiple Choice

Q 83Q 83

The number of avalanche fatalities in Colorado for the last nine seasons was reported as 7, 1, 6, 6, 7, 5, 8, 2, 3.What type of distribution do the numbers represent?
A) unimodal
B) bimodal
C) multimodal
D) nonmodal

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Multiple Choice

Q 84Q 84

For a data set that has been skewed due to outliers, what measure of central tendency is most accurate and should be reported?
A) mean
B) median
C) mode
D) variance

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Multiple Choice

Q 85Q 85

When data are based on a nominal scale of measurement, what measure of central tendency should be used?
A) mean
B) median
C) mode
D) variance

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Multiple Choice

Q 86Q 86

A comparison of the most expensive house in a neighborhood and the least expensive house in a neighborhood would involve computation of which statistic?
A) range
B) standard deviation
C) variance
D) central tendency

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Multiple Choice

Q 87Q 87

The range as a measure of variability is problematic because:
A) it does not represent the spread of the distribution.
B) calculations of the range are frequently full of errors.
C) it is expressed in squared units.
D) it relies on the most extreme scores, which could be outliers.

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Multiple Choice

Q 88Q 88

Which measure of variability is the average of the squared deviations from the mean?
A) variance
B) standard deviation
C) range
D) central tendency

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Multiple Choice

Q 89Q 89

The standard deviation is most commonly used to get a sense of how far the typical score of a distribution differs from the mean.In computing the standard deviation, why is it necessary to square the deviations from the mean for each score?
A) The deviations are too small to have a variance without being squared.
B) There is no variability in the deviations of the scores prior to squaring.
C) Squaring numbers is a required step in calculating all measures of variability.
D) The deviations sum to zero due to negative and positive values.

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Multiple Choice

Q 90Q 90

Of the four types of population parameters used to describe any distribution, which parameter describes how far the observations scatter around the central value?
A) mean
B) standard deviation
C) skewness
D) interquartile range

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Multiple Choice

Q 91Q 91

What measure of variability is the square root of the average of the squared deviations from the mean?
A) variance
B) standard deviation
C) range
D) central tendency

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Multiple Choice

Q 92Q 92

The variance calculated on 22 scores is equal to 28.93.What is the standard deviation?
A) 1.32 units
B) 1.32 units squared
C) 5.38 units
D) 5.38 units squared

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Multiple Choice

Q 93Q 93

EuroTravel Agency is marketing overseas trips to college students but needs to keep in mind the average student's budget when setting their rates.In order to maximize the number of trips sold, the agency decides to market to the interquartile range of the students, based on their reported budgets.Who is in this group of students?
A) students with the highest budgets only
B) students with the lowest budgets only
C) students with budgets between the 25th percentile and 50th percentile of the group
D) students with budgets between the 25th percentile and 75th percentile of the group

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Multiple Choice

Q 94Q 94

Measures of central tendency and variability are calculated to describe the nature of charitable giving each year.These figures are computed for the "average" American citizen.In that case, the mean calculated would be taken as:
A) a population parameter.
B) a measure of variability.
C) a sample statistic.
D) part of a five-number summary.

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Multiple Choice

Q 95Q 95

The numerical summary characteristics of a population are called _____, while the numerical summary characteristics of a sample are called _____.
A) parameters; variance
B) parameters; statistics
C) statistics; parameters
D) statistics; sum of squares

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Multiple Choice

Q 96Q 96

The dean of a local college needs to drop one course from the art program.She decides to pick the course with the lowest average enrollment rate from the previous four semesters.The enrollments of three courses she is considering are Photography-30, 20, 12, and 22; Film Editing-11, 29, 27, and 29; and Abstract Art-18, 22, 21, and 24.Which class has the lowest mean enrollment over the past four semesters?
A) Photography
B) Film Editing
C) Abstract Art
D) All three classes have the same mean.

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Multiple Choice

Q 97Q 97

The most common score of a distribution is referred to as the:
A) mean.
B) median.
C) mode.
D) range.

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Multiple Choice

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Multiple Choice

Q 99Q 99

These are a basketball player's number of points scored in five games: 21, 2, 15, 19, 15.Which score seems to be an outlier?
A) 2
B) 15
C) 19
D) 21

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Multiple Choice

Q 100Q 100

When looking at a distribution of data with a possible outlier, it is important to keep in mind the range of all scores because an extremely high or low outlier may skew the _____of the data set.
A) parameters
B) sum of squares
C) mean
D) mode

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Multiple Choice

Q 101Q 101

The Lee family is looking to buy a house in one of two suburban areas just outside a major city, and air quality is a top priority for them.One suburb advertises the use of hybrid cars and solar panels, while the other focuses on its convenient bus routes and availability of Hummer dealerships.Is the mean or median the better measure to use for deciding which area has better air quality? (Hint: These populations are skewed.)
A) median, because it is less biased by skewness being dependent on the middle score
B) mean, because it is always the best measure of central tendency in any population
C) median, because it is never affected by outliers
D) mean, because it represents the balance of the distribution

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Multiple Choice

Q 102Q 102

The _____ is a measure of variability that is calculated by taking the difference of the highest and lowest scores in the distribution.
A) standard deviation
B) range
C) variance
D) central tendency

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Multiple Choice

Q 103Q 103

Measures of central tendency and variability are calculated to describe the nature of charitable giving each year.These figures are computed for the "average" American citizen.Which of these is a possible value for the variance in dollars given?
A) -$47.26
B) $47.26
C) $38.45 to $47.26
D) $47.26 squared dollars

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Multiple Choice

Q 104Q 104

When the mean is presented in research articles, it is most often accompanied by the _____ as a measure of variability.
A) range
B) variance
C) standard deviation
D) interquartile range

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Multiple Choice

Q 105Q 105

The _____ is equal to the square root of the _____.
A) variance; standard deviation
B) standard deviation; variance
C) central tendency; mean
D) mean; central tendency

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Multiple Choice

Q 106Q 106

Sylvie examined the GRE verbal scores of 10 first-year graduate students in her creative writing class to see the variability.Sylvie found the variance to be 18.225.What is the standard deviation?
A) 67.5
B) 135.0
C) 1822.5
D) 9112.5

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Multiple Choice

Q 107Q 107

Which of these is NOT a reason to use the interquartile range instead of the range?
A) The range includes the smallest-to-largest observations and may be unreliable.
B) The interquartile range can help assess skew better than the range can alone.
C) The interquartile range is not based on the minimum and maximum scores.
D) The interquartile range is more likely to account for outliers.

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Multiple Choice

Q 108Q 108

The last value in a five-number summary is the:
A) 75th percentile.
B) minimum value.
C) median.
D) maximum value.

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Multiple Choice