Deck 3: Measures of Central Tendency and Variability

Question 1

The mode of a distribution of scores:

A)is the most easily computed index of central tendency
B)is simply the score that occurs most frequently
C)has the highest "peak" in a graph of a distribution of scores
D)all of these

Answer 1

all of these

Question 2

The term "central tendency" refers to _____.

A)an average
B)a score around which other scores tend to cluster
C)both a and b
D)neither a nor b

Answer 2

both a and b

Question 3

Compute the median of the following set of scores: 106,106,109,110,113,121,121.

A)109.5
B)110
C)106 and 121
D)cannot be determined from information given

Answer 3

110

Question 4

As a measure of central tendency,the median _____ the absolute difference between it and the scores in the distribution.

A)minimizes
B)maximizes
C)summarizes
D)none of these

Question 5

When there is an even number of scores,the median is the _____.

A)most frequently occurring score
B)arithmetic average of the scores
C)arithmetic average of the two middle scores
D)arithmetic average of the two most extreme scores

Question 6

The sum of signed deviations about the mean will always equal _____.

A)10
B)-10
C)the sum of squares
D)0

Question 7

Measures of _____ indicate the extent to which scores within a set differ from one another.

A)central tendency
B)variability
C)differential tendency
D)none of these

Question 8

Most of the inferential statistics used by behavioral scientists make use of the _____ as a measure of central tendency.

A)mean
B)median
C)mode
D)all are used with equal frequency

Question 9

The _____ is simply the arithmetic average of a set of scores.

A)median
B)mean
C)mode
D)standard deviation

Question 10

The mean,median,and mode are applicable to:

A)continuous variables only
B)discrete variables only
C)continuous and discrete variables
D)interval and ratio level variables only

Question 11

Which of the following statements is true of the mode of any set of scores?

A)It is the score which occurs most frequently.
B)It is always less than the mean.
C)Both a and b.
D)Neither a nor b.

Question 12

Eight psychology students took a well-known I.Q.test and achieved the following scores: 96,98,108,110,115,120,121,142.The median score for these students is _____.

A)96
B)112.5
C)113.5
D)115

Question 13

_____ refers to the "average" score in a set of scores.

A)central tendency
B)variability
C)average deviation
D)none of these

Question 14

The major problem with the mode as a measure of central tendency is that:

A)there can be only one modal score
B)there can be more than one modal score
C)the mode is insensitive to variability
D)the mode is insensitive to kurtosis

Question 15

The _____ is the point in the distribution of scores that divides the distribution into two equal parts.

A)mean
B)mode
C)median
D)standard deviation

Question 16

Which of the following statements is true of a median score?

A)It divides a distribution in half.
B)It may not have been a score actually achieved.
C)Both a and b.
D)Neither a nor b.

Question 17

Suppose a researcher was interested in determining the effect of an experimental drug on the lifespan of laboratory rats.Shown below is a summary of the lifespans,in months,for laboratory animals administered the drug.Compute the median number of months the animals survived.

A)3.1
B)25
C)3.0
D)2.9

Question 18

The mean is computed by summing all of the scores and then dividing the sum by the:

A)standard deviation
B)mean divisor
C)total number of scores
D)average number of scores

Question 19

If you were to randomly select one score from a set of scores,the score most likely to be selected _______.

A)would be equal to the medium of the set of scores
B)would be equal to the mode of the set of scores
C)would be equal to the mean of the set of scores
D)can vary with the numerical values of the individual scores

Question 20

Consider the following scores achieved by subjects taking a standard IQ test: 68,83,93,100,101,103,106,120.The mode is ______.

A)93
B)101
C)97.88
D)none of these

Question 21

If you subtract the mean from each score in a distribution,you would obtain a set of _____.

A)signed deviation scores
B)standard individual deviation scores
C)absolute deviation scores
D)signed discrepancy scores

Question 22

The sum of squared deviations from the _____ will always be _____ the sum of squared deviations around any other value.

A)median;less than
B)mode;equal to
C)mean;greater than
D)mean;less than

Question 23

Distributions of scores can have _____.

A)identical standard deviations with different means
B)identical means with different standard deviations
C)either a or b
D)neither a nor b

Question 24

The _____ is the highest score minus the lowest score.

A)variance
B)standard deviation
C)interquartile range
D)range

Question 25

The positive square root of the variance is the _____.

A)root square mean
B)standard deviation
C)variance square root
D)absolute squared deviation

Question 26

The interquartile range has been criticized because it does not take into account:

A)the sum of squares
B)all of the scores in the distribution
C)none of these

Question 27

The extent to which scores in a distribution differ is indicated by _____.

A)measures of central tendency
B)measures of variability
C)the result of subtracting each score from the median
D)the average of the mean and the standard deviation

Question 28

If SS for 30 students is 900,what is the variance?

A)5.47
B)more than 30
C)less than 30
D)exactly 30

Question 29

In a normal distribution,the _____.

A)mean is usually higher than the mode
B)median is usually lower than the mean
C)mean,median,and mode might be equal
D)mean,median,and mode are always equal

Question 30

The _____ is the difference between the highest and lowest scores after the top 25% of the scores and the bottom 25% of the scores have been eliminated from the data.

A)range
B)interquartile range
C)intermediate range
D)intertertial range

Question 31

Compute the sum of squares for the following data set: 2,2,3,6,9,13,14.

A)156
B)22.28
C)7
D)none of these

Question 32

The median _____ the sum of the _____ deviations.

A)minimizes;signed
B)minimizes;unsigned
C)maximizes;signed
D)maximizes;unsigned

Question 33

Considering the distribution -2,-4,-6,-8,-10,the SS is _____.

A)40
B)8
C)-40
D)-8

Question 34

A teacher wants to determine the mean score of students taking a newly developed test.Her students scored as follows: 40,45,60,65,70,70,70,80,90,100.Compute the mean for the class.

A)69
B)70
C)69.5
D)none of these

Question 35

SS is the _____.

A)sum of standard scores
B)sum of squared deviations from the mean
C)sum of standard deviations from the mean
D)sum of standard deviations from the median

Question 36

If a researcher were to subtract the mean of a distribution from each score in that distribution and add the differences,the resulting value would _____.

A)be equal to the median
B)always be zero
C)be greater than the mode
D)depend upon the scores that make up the distribution

Question 37

The _____ is the measure of central tendency that is most sensitive to extreme values in a distribution.

A)mode
B)standard deviation
C)median
D)mean

Question 38

The mean of a set of scores is best described as _____.

A)a simple arithmetic average
B)an arithmetic average weighted by the number of subjects
C)usually equal to the mode
D)relatively free of the effects of extreme values

Question 39

After giving a test to all members of his college class,a professor found that the scores totaled 1500 and the mean was 75.How many students took the test?

A)25
B)20
C)22
D)cannot be determined without additional information

Question 40

Given the data set 8,8,8,7,5,6,2,2,what is the range?

A)8
B)2
C)5.75
D)6

Question 41

The variance is the:

A)sum of squares divided by N
B)the average squared deviation from the mean
C)a and b
D)neither a nor b

Question 42

One problem with the sum of squares as an index of variability is that its size depends not only on the amount of _____ among the scores,but also on the _____ of scores.

A)variability;number
B)skewness;kurtosis
C)error;number
D)none of these

Question 43

If a distribution is less peaked than another,it is said to be more _____;if it is more peaked than another,it is said to be more_____.

A)skewed;variable
B)leptokurtic;variable
C)platykurtic;leptokurtic
D)leptokurtic;platykurtic

Question 44

When there is an odd number of scores,the median

A)is the arithmetic average of the middle two scores.
B)is the middle score.
C)occurs within the real limits of the middle score(s)when there are duplications of the middle score(s).
D)both a and c
E)both b and c

Question 45

Use of Greek notation implies that the parameters describe ____ characteristics.

A)sample
B)normally distributed
C)random
D)population

Question 46

_____ refer(s)to the tendency for scores to cluster on one side of the mean in some distributions.

A)Unbalancing
B)Skewness
C)Both a and b
D)Neither a nor b

Question 47

In positively skewed distributions,most scores occur _____ the mean and only a relatively few extreme scores occur _____ it.

A)below;above.
B)at;above.
C)below;above
D)at;below

Question 48

How would you describe the relationship between the mean,median,and the mode in a positively skewed distribution?

A)mean > median > mode
B)mean < median < mode
C)mean = median = mode
D)mean > mode > median

Question 49

When presenting measures of central tendency and variability,most researchers report _____ and_____ ,which are the most _____ descriptive statistics.

A)means;standard deviations;frequently used
B)means;standard deviations;precisely defined
C)means;standard deviations;generally accurate
D)none of these

Question 50

Which of the following sets of data is bimodal?

A)75,85,95,105,105,105,115,125,135,135,135,145,155
B)53,62,71,80,80,80,94,99,100,132,132,145
C)2,2,2,3,3,3,3,4,5,6,7,7,7,8,8
D)20,30,30,30,30,40,50,60,70,90,100,100,100,112

Question 51

The mean is

A)the most frequently occurring score.
B)the mathematical average.
C)the midpoint of the distribution.

Question 52

The mode is the most appropriate measure of central tendency when the scale of measurement used is

A)nominal.
B)ordinal.
C)interval.

Question 53

Which measure of central tendency is affected by extreme scores?

A)mode
B)median
C)mean

Question 54

Distributions of scores can have:

A)identical variabilities but very different central tendencies
B)identical central tendencies but very different variabilities
C)a and b
D)neither a nor b

Question 55

Measures of central tendency are measures of

A)deviations.
B)location.
C)distance.
D)extremes.

Question 56

Based on the Method of Presentation section of Chapter 3,which of the following symbols should be used to report the mean in a behavioral science journal,according to the American Psychological Association (APA)?

A)M
B)m
C)

Question 57

Based on the Method of Presentation section of Chapter 3,the symbol n indicates

A)the sample size in a particular group.
B)the total sample size in the study.
C)the population sample size.
D)the number of groups in the study.

Question 58

The best answer to the question,"What value indicates a large standard deviation?" is:

A)any value greater than 10.00
B)any value greater than 100.00
C)it depends on the variability
D)it depends on what is being measured

Question 59

The mean of a _____ skewed distribution will always be _____ than the median.

A)positively;less
B)negatively;less
C)negatively;greater
D)normal;less

Question 60

The standard deviation is the:

A)square root of the sum of squares
B)positive square root of the variance
C)negative square root of the variance
D)sum of squares divided by N

Question 61

If you subtract the mean from each X score and sum these scores,the sum will equal:

A)1
B)a number greater than 1
C)0
D)cannot be determined from the information given

Question 62

The interquartile range is sometimes preferred over the range because it

A)does not involve the median.
B)takes the most extreme scores into account.
C)is not based on the most extreme scores.
D)does not take into account all of the scores in a distribution.

Question 63

The symbol used for the population variance is _____ and the symbol used for the population standard deviation is _____.

A)s;s².
B)s²,s.
C)s;s²
D)s²;s

Question 64

What statement below is TRUE in regards to a normal distribution?

A)Distribution unequal
B)Scores are skewed
C)Mean,median and mode are equal
D)Theoretical in nature
E)Both c & d

Question 65

What measure of central tendency is used with a nominal scale?

A)Mean
B)Median
C)Mode
D)Both mean and mode
E)All of these

Question 66

The variance is the

A)average of the deviations from the mean divided by N.
B)average of the squared deviations from the mean.
C)sum of the deviations from the mean divided by N.
D)sum of the squared deviations from the mean.

Question 67

If a distribution is positively skewed,this means that

A)the scores tend to be clustered towards the high end of the scale.
B)the scores tend to be clustered towards the low end of the scale.
C)the scores are positive numbers.
D)the distribution is highly peakeD.

Question 68

Because discrete variables are only measured with whole numbers,fractions are never included when reporting the means for discrete variables.

Question 69

Measures of Central tendency are an example of_____.

A)inferential statistics
B)descriptive statistics
C)nonparametric statistics
D)both descriptive and nonparametric statistics

Question 70

One problem with the sum of squares as a measure of variability is that its size depends on _____,as well as the variability among scores.

A)the total N
B)extreme scores
C)the mode
D)the standard deviation

Question 71

When comparing two different distributions,which of the following is not possible?

A)both have the same mean,but different standard deviations
B)both have the same standard deviation,but different means
C)both have the same mean and the same standard deviation
D)both have different means and different standard deviations
E)all of these are possible

Question 72

When referring to qualitative variables,maximum variability occurs when

A)the standard deviation is a large number.
B)the number of individuals is evenly divided among the possible categories.
C)all of the individuals fall into a single category.
D)none of these

Question 73

If a distribution is less peaked than another,it is said to be more____;if it is more peaked than another,it is said to be more_____.

A)Skewed;variable
B)Leptokuritc;variable
C)platykurtic;leptokurtic
D)leptokurtic;platykurtic

Question 74

The range indicates the

A)average distance from the median.
B)distance between the highest and lowest scores.
C)average variability among all of the scores.

Question 75

The standard deviation is the most easily interpreted measure of variability because it

A)does not include extreme scores.
B)is measured in square units.
C)is in the original unit of measurement.
D)is usually a number larger than the variance.

Question 76

Measures of central tendency include the following EXCEPT _____.

A)mean
B)median
C)mode
D)range
E)All of these are measures of central tendency.

Question 77

_____refer(s)to the tendency for scores to cluster on one side of the mean in some distributions.

A)Unbalancing
B)Skewness
C)Kurtosis
D)Both skewness and kurtosis
E)None of these

Question 78

Which of the following statements is true about the median?

A)It divides a distribution in half.
B)It may not have been a score actually in the distribution
C)Approximately 50% of the scores will be above the median and 50% below.
D)All of these are correct.

Question 79

Eight psychology students took a well-known I.Q.test and achieved the following scores: 96,98,108,110,115,120,121,142.The mean I.Q.is _____.

A)130
B)113.80
C)113.75
D)115
E)None of these

Question 80

The mean of a _____skewed distribution will always be _____than the median.

A)positively;less
B)negatively;less
C)negatively;greater
D)normal;less