Module 4

Question 1

The range of the theoretical normal curve is
A) Unlimited
B) 6S
C) 5S
D) 4S

Answer 1

A) Unlimited

Question 2

Which is not a property of the normal curve?
A) It is unimodal
B) Its mean may take various values
C) Its standard deviation may take several values
D) None of the above

Answer 2

D) None of the above

Question 3

A z score in a given distribution is -.5. If the mean of this distribution is 130 and the standard deviation is 20, the equivalent raw score in that distribution is
A) 129.5
B) 120
C) 110
D) Cannot be determined without further information

Answer 3

B) 120

Question 4

A z score in a given distribution is -2. If the distribution is normal and its mean is 40, the equivalent raw score in that distribution
A) Is 38
B) Is 20
C) Lies above 40
D) Cannot be determined without further information

Answer 4

D) Cannot be determined without further information

Question 5

College Board scores have a mean of 500 and a standard deviation of 100.  On this scale, a score of 450 is the equivalent of
A) z = -1
B) z = -0.5
C) z = 0
D) None of the above

Answer 5

B) z = -0.5

Question 6

If a set of raw scores is positively skewed, the set of z scores derived from them will be
A) Positively skewed
B) Very close to a normal distribution, but slightly positively skewed
C) Symmetrical, but not normal
D) Normally distributed

Answer 6

A) Positively skewed

Question 7

The percent of cases in a normal distribution falling between z = -.67 and z = +.67 is approximately
A) 25%
B) 50%
C) 67%
D) 134%

Answer 7

B) 50%

Question 8

In a normal distribution of 200 cases, how many fall between z = -1.5 and z = +1.5?
A) 173
B) 87
C) 43
D) 27

Answer 8

A) 173

Question 9

In a normal distribution of 200 cases, how many fall above z = +1.25?
A) 39
B) 79
C) 21
D) 11

Answer 9

C) 21

Question 10

In a normal distribution with x̄ = 50 and S = 10, what proportion of cases falls between 45 and 55?
A) 0.3085
B) 0.3830
C) 0.6170
D) 0.1915

Answer 10

B) 0.3830

Question 11

In a normal distribution with x̄ = 50 and S = 10, what proportion of cases falls above a score of 62?
A) 0.7698
B) 0.3849
C) 0.1151
D) 0.0478

Answer 11

C) 0.1151

Question 12

In a normal distribution of 400 scores with x̄ = 50 and S = 10, how many fall below 35?
A) 17
B) 27
C) 37
D) 47

Answer 12

B) 27

Question 13

In a normal distribution of 400 scores with x̄ = 50 and S = 10, how many fall between 50 and 60?
A) 98
B) 142
C) 68
D) 137

Answer 13

D) 137

Question 14

In a normal distribution, the bottom 75% of the cases fall below what z score?
A) +0.50
B) -0.84
C) +1.28
D) +0.67

Answer 14

D) +0.67

Question 15

In a normal distribution of 200 cases, the bottom 40 cases fall below what z score?
A) +0.50
B) -0.84
C) +1.28
D) +0.67

Answer 15

B) -0.84

Question 16

In a normal distribution of 200 cases, what z score divides the top 20 cases from the bottom 180?
A) +0.50
B) -0.84
C) +1.28
D) +0.67

Answer 16

C) +1.28

Question 17

In a normal distribution, the most extreme 5% of the cases fall beyond z =
A) ±1.65
B) ±2.58
C) ±1.96
D) ±1.80

Answer 17

C) ±1.96

Question 18

In a normal distribution, the middle 20% of the cases fall between what two z scores?
A) -0.52 and +0.52
B) -0.84 and +0.84
C) -1.28 and +1.28
D) -0.25 and +0.25

Answer 18

D) -0.25 and +0.25

Question 19

In a normal distribution with x̄ = 50 and S = 10, the bottom 80% of the cases fall below what score (rounded)?
A) 63
B) 54
C) 61
D) 58

Answer 19

D) 58

Question 20

In a normal distribution with x̄ = 50 and S = 10, the middle 50% of the cases fall between what two scores (rounded)?
A) 41 and 49
B) 43 and 57
C) 38 and 62
D) 45 and 55

Answer 20

B) 43 and 57

Question 21

In a normal distribution with x̄ = 50 and S = 10, the bottom 30% of the cases fall below what score (rounded)?
A) 45
B) 40
C) 38
D) 47

Answer 21

A) 45

Question 22

Three scores in a distribution are 20, 25, and 35. The z score equivalents of the first two are, respectively, -1.00 and -.50. The z score equivalent of the third score
A) Is 0
B) Is +0.50
C) Is +1
D) Cannot be determined from the above information

Answer 22

B) Is +0.50

Question 23

What is not a necessary characteristic of a set of standard scores?
A) Mean is set at a standard value
B) Standard deviation is set at a standard value
C) Distribution follows the normal curve
D) All of the above are necessary characteristics of a set of standard scores

Answer 23

C) The distribution follows the normal curve

Question 24

A score of 32 probably represents the poorest performance in a distribution having which set of characteristics?
A) x̄ = 50, S = 20
B) x̄ = 40, S = 2
C) x̄ = 42, S = 10
D) x̄ = 60, S = 30

Answer 24

B) x̄ = 40, S = 2

Question 25

The mean of a set of z scores is
A) 1
B) 0
C) Indeterminate
D) The same as the mean of raw scores from which the z scores are derived

Answer 25

B) 0

Question 26

z scores from two different score distributions are comparable only if
A) The means and standard deviations are equal
B) The numbers of cases are approximately the same
C) The reference groups are equivalent
D) All of the above

Answer 26

C) The reference groups are equivalent

Question 27

The standard deviation of a set of z scores is
A) The same as the standard deviation of the set of raw scores
B) Always smaller than the standard deviation of the set of raw scores
C) The same as the standard deviation of the set of raw scores if they are normally distributed
D) 1

Answer 27

D) 1

Question 28

A set of raw scores (x̄ = 78 and S = 8) is converted to a set of standard scores (x̄ = 50 and S = 10).  A raw score of 90 is equivalent to a standard score of
A) 58
B) 65
C) 68
D) 72

Answer 28

B) 65

Question 29

A score of 650 is earned on a test for which x̄ = 500 and S = 100.  An equivalent score on a scale where x̄ = 100 and S = 10 is
A) 105
B) 120
C) 110
D) 115

Answer 29

D) 115

Question 30

A score of 85 is earned on a test in which x̄ = 100 and S = 15.  An equivalent score on a scale where x̄ = 50 and S = 10 is
A) 35
B) 40
C) 45
D) None of the above

Answer 30

B) 40

Question 31

Standard scores obtained from different distributions may be compared if:
A) The reference groups are comparable
B) The shapes of the distributions are similar
C) Both (A) and (B)
D) Irrespective of norm groups and shape of diustributions

Answer 31

C) Both (A) and (B)

Question 32

A set of raw scores (x̄ = 48 and S = 9) is transformed to a set of IQ scores (x̄ = 100 and S = 15).  A raw score of 45 is equivalent to an IQ score of
A) 95
B) 92
C) 88
D) 98

Answer 32

A) 95

Question 33

In a normal distribution of x̄ = 50 and S = 10, P18 is a score of (rounded):
A) 43
B) 41
C) 38
D) 36

Answer 33

B) 41

Question 34

In a normal distribution of x̄ = 50 and S = 10, a score of 58 is:
A) P79
B) P71
C) P68
D) P65

Answer 34

B) P71

Question 35

In a normal distribution of scores, the percentile rank of a z of -.10 is:
A) 54
B) 38
C) 46
D) 4

Answer 35

C) 46

Question 36

In a normal distribution of scores, P65 is equivalent to a z of:
A) +1.03
B) +0.84
C) +0.39
D) +0.25

Answer 36

C) +0.39

Question 37

In a normal distribution, the interscore distance would be greatest for which interval?
A) P5-P10
B) P45-P50
C) P75-P80
D) The same for all above intervals

Answer 37

A) P5-P10

Question 38

For normal distributions, percentile ranks tend to exaggerate difference between persons at the low, middle, or high end of the scale?

Answer 38

Middle

Question 39

Given: x̄1 > x̄2 , d = +.65, and both distributions are normally distributed.  From this, you can conclude that the mean of the second distribution falls approximately at the \_\_\_\_\_ percentile of the first distribution.
A) 55th
B) 63rd
C) 74th
D) 82nd

Answer 39

C) 74th