Deck 3: Measures of Variability

Question 1

When new scores that are close to the mean are added to any distribution, there is a fairly high probability that the range will

A) remain unaffected
B) be reduced
C) be increased
D) new scores may never be added to a distribution

Answer 1

A

Question 2

If 50% of the cases fall above a given point, then 50% must also fall

A) below that point
B) between the mean and median
C) between the first and fifth deciles
D) none of these, since the distribution can never account for 100% of the

Answer 2

A

Question 3

Of the following, which can be calculated even though the data are in ordinal form?

A) interquartile range
B) interdecile range
C) the middle-most 50% of the scores
D) all of these

Answer 3

D

Question 4

One major defect of the range is that

A) it includes the entire width of the distribution
B) it is based on only two scores
C) it is not a measure of variability
D) all of these

Question 5

The standard deviation is a measure of

A) how far all the scores vary from the mean
B) how far the middle-most 50% of cases vary from the mean
C) how far the highest and lowest scores vary from each other
D) central tendency

Question 6

The third quartile begins between the

A) 1st and 5th deciles
B) 2nd and 3rd deciles
C) 4th and 6th deciles
D) 7th and 8th deciles

Question 7

Specific points may be located on any distribution by using the

A) percentile
B) quartile
C) decile
D) all of these

Question 8

Of the following, which should not be calculated when the data are in ordinal form?

A) median
B) quartile
C) decile
D) mean

Question 9

A score which is at the 95th percentile must exceed

A) at least 5% of the scores
B) at least 95% of the scores
C) at least 45% of the scores
D) at least the lowest 47.50% of the scores

Question 10

When a student takes a 600-item standardized test and is told he/she is at the 70th percentile, it means that the student

A) answered 30% of the items correctly
B) answered more than 70% of the items correctly
C) answered exactly 420 items correctly
D) none of these

Question 11

The concept of "individual differences" may best be described by

A) the mode
B) the median
C) the measures of central tendency
D) the measures of variability

Question 12

A score which falls at the 50th percentile must always be at the

A) mean
B) mode
C) median
D) none of these

Question 13

The fifth decile coincides with the

A) 50th percentile
B) 2nd quartile
C) median
D) all of these

Question 14

The difference between the highest and lowest scores in any distribution is called

A) the deviation score
B) the standard deviation
C) the range
D) none of these

Question 15

The first quartile coincides with the

A) first percentile
B) twenty-fifth percentile
C) seventy-fifth percentile
D) median

Question 16

The interdecile range lies between the

A) 3rd and 7th deciles
B) 2nd and 8th deciles
C) 1st and 9th deciles
D) median and the 10th decile

Question 17

The interquartile range lies between

A) the median and the third quartile
B) the median and the first quartile
C) the median and the lowest score in the distribution
D) the first and third quartiles

Question 18

The measure of the entire width of the distribution is called the

A) range
B) percentile
C) quartile
D) b and c, but not a

Question 19

Of the following, the measure(s) of variability is (are),

A) the range
B) the standard deviation
C) the mode
D) a and b, but not c

Question 20

The interquartile range includes the middle-most

A) 25% of the cases
B) 50% of the cases
C) 75% of the cases
D) 95% of the cases

Question 21

A platykurtic distribution always has

A) a relatively small standard deviation
B) a relatively large standard deviation
C) a standard deviation of zero
D) a few extreme scores at just one end of the distribution

Question 22

The standard deviation demands that the data form be at least

A) nominal
B) ordinal
C) interval
D) none of these, since the standard deviation has no data-scale requirements

Question 23

The deviation score is

A) exactly the same as the standard deviation
B) only the same as the standard deviation when variability is small
C) only the same as the standard deviation when variability is large
D) the difference between the raw score and the mean

Question 24

The only time the standard deviation may equal zero, is when

A) the range is less than 50
B) every score in the distribution is the same
C) the range is negative
D) none of these, since the standard deviation may never be equal to zero

Question 25

The smaller the standard deviation

A) the more leptokurtic the resulting curve
B) the more mesokurtic the resulting curve
C) the more platykurtic the resulting curve
D) the higher the chance of the curve being bimodal

Question 26

When the standard deviation has a negative value, then

A) most scores were above the mean
B) most scores were below the mean
C) the distribution is badly skewed
D) none of these, since the standard deviation can never be negative

Question 27

The standard deviation must always be calculated with reference to the

A) decile
B) median
C) mode
D) mean

Question 28

The more heterogeneous the distribution of scores,

A) the smaller the standard deviation
B) the larger the standard deviation
C) the more the distribution tends to be skewed
D) the greater the chance of excluding extreme scores

Question 29

You know you've made a math error whenever the standard deviation is

A) smaller than the variance
B) negative
C) smaller than the range
D) b and c, but not a

Question 30

The only time the range may equal zero, is when

A) the standard deviation is less than 1.00
B) every score in the distribution is the same
C) the standard deviation is negative
D) the interdecile range is skewed to the left

Question 31

When a deviation score has a negative value, then

A) the raw score is below the mean
B) the raw score is above the mean
C) the raw score equals the mean
D) none of these, since deviation scores can never be negative

Question 32

The higher the value of the standard deviation, the higher the

A) percentile
B) decile
C) quartile
D) none of these

Question 33

A distribution with a large standard deviation must also have a large

A) number of scores near the mean
B) number of scores near the median
C) variance
D) none of these

Question 34

If two distributions have the same mean, then they must also have the same

A) median
B) mode
C) standard deviation
D) none of these

Question 35

Of two golfers, each of whom drives the ball the same average distance, the one with the smaller standard deviation would be

A) the more consistent
B) the less consistent
C) the one more apt, on a given shot, to drive the ball further
D) none of these, since they both drive the same average distance

Question 36

The variance is equal to

A) the standard deviation squared
B) the square-root of the standard deviation
C) twice the standard deviation
D) none of these

Question 37

If two football running-backs have the same yards-per-carry average, but player A has a larger standard deviation than player B, then

A) player A has a greater chance of making a long gain
B) player A has a greater chance of being caught for a loss
C) player A is the more consistent runner
D) a and b, but not c

Question 38

The term which defines the flatness or peakedness of a curve is

A) kurtosis
B) range-values
C) central tendency
D) homoscedasticity

Question 39

If the value of the standard deviation is greater than the value of the range, then

A) the distribution is heterogeneous
B) the distribution is homogeneous
C) the distribution is skewed
D) none of these, since the standard deviation must always be less than the

Question 40

When most scores cluster closely around the mean, the curve is

A) asymmetrical
B) platykurtic
C) shaped like a U
D) leptokurtic

Question 41

The interquartile range was equal to

A) 60
B) 50
C) 20
D) 0

Question 42

The ninth decile coincided with an IQ of

A) 75
B) 100
C) 125
D) 130

Question 43

The standard deviation was equal to approximately

A) 0
B) 10
C) 15
D) cannot tell, since not enough information is provided

Question 44

Two distributions may have the same mean, and yet have different standard deviations.

Question 45

The second quartile coincided with an IQ of

A) 70
B) 75
C) 100
D) 125

Question 46

The fifth decile coincided with an IQ of

A) 70
B) 75
C) 100
D) 125

Question 47

The first decile coincided with an IQ of

A) 75
B) 90
C) 100
D) 130

Question 48

The interquartile range includes only the middle-most 25% of the distribution.

Question 49

A negative standard deviation indicates that most of the scores were below the mean.

Question 50

The interdecile range was equal to

A) 60
B) 50
C) 20
D) 0

Question 51

If two distributions have the same mean and same range, then they must also

A) have the same standard deviation
B) when graphed, have the same kurtosis
C) have the same variance
D) none of these

Question 52

The distribution with the largest standard deviation necessarily has the largest range.

Question 53

The standard deviation may only be computed with reference to the mean.

Question 54

If the range on a mesokurtic distribution is equal to 60, then the standard deviation will be approximately equal to

A) 10
B) 360
C) .17
D) impossible to determine from the facts given

Question 55

The range was equal to

A) 60
B) 50
C) 20
D) 0

Question 56

The third quartile coincided with an IQ of

A) 75
B) 90
C) 110
D) 125

Question 57

A leptokurtic distribution has a relatively small standard deviation.

Question 58

When an extremely homogeneous set of scores is graphed, then the resulting frequency distribution curve is

A) platykurtic
B) leptokurtic
C) mesokurtic
D) bimodal

Question 59

Of the following, indicate which is not a measure of variability

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

Question 60

When the range of a unimodal distribution equals approximately 6 times the standard deviation, then the curve is most likely to be

A) skewed
B) leptokurtic
C) platykurtic
D) mesokurtic

Question 61

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
Find the standard deviation for the group.

Question 62

The standard deviation may never be larger than the range. 33

Question 63

The median must always coincide with the fifth decile.

Question 64

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
Find the range for the group.

Question 65

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
Is the distribution skewed?

Question 66

Kurtosis refers to the flatness or peakedness of the curve.

Question 67

If you were to receive a score on an exam which placed you at the 90th percentile, then 90% of those taking the test scored below you.

Question 68

If a student takes a test and gets a raw score which is at a point that is greater than 70% of all students taking the same test then the student's score is at the 70th percentile.

Question 69

The standard deviation of any distribution must always equal one-sixth of the range.

Question 70

If a student takes a test and gets 70% of the items right, then the student's score is at the 70th percentile.

Question 71

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
In comparing your predicted value with the actual value for the standard deviation, what conclusions might you draw regarding the shape of the distribution.

Question 72

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
What percentage of the group scored in the danger zone (13 or above)?

Question 73

The smallest possible standard deviation is equal to zero.

Question 74

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
Find the mean score for the group.

Question 75

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
Find the median score for the group.

Question 76

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
Find the mode for the group.

Question 77

DQuestions 74 through 82 will be based on the following: The Children's Depression Inventory (CDI), developed from Beck's Depression Inventory is a self-report instrument with 27 sets of statements. Higher scores indicate higher levels of depression. Scores above 13 are said to indicate a Major Depressive Disorder (MDD) and few false positives have been reported. A random sample of 20 fifth grade students was selected and given the test. Their scores were as follows: 9,10,11,9,8,9,17,2,7,11,6,12,9,10,9,9,8,10,14,1.
If the distribution had been absolutely normal, what standard deviation (standard value) would you have predicted for a group of scores with this range value?

Question 78

The higher the value of the standard deviation, then the more the scores are spread out around the mean.

Question 79

The higher the value of the mean, then the higher the value of the range.

Question 80

When the vast majority of scores cluster tightly around the mean, the graphed distribution is leptokurtic.