Review Questions and Practice Problems
PART A (ANSWERS PROVIDED IN APPENDIX C)
PART B
1. Which of the following would least likely result
in normally distributed data?
For problems 5 through 8, assume the data are normally distributed, with a mean of 75, a standard deviation
of 9, and an N = 36.
A. Age of 5,000 individuals when suffering their
first heart attack
B. Heights of 5,000 ten-year-old boys
C. Weights of 5,000 preschool children
D. Percent fat of 5,000 sixteen-year-old girls
2. Which of the following most likely represents the
worst performance?
5. What is the z-score for a raw score of 80?
6. What is the T-score for a raw score of 87?
A. Percentile of 49
B.
T-score of 39
C.
z-score of –0.8
3. If the mean of a distribution is 500 and the
variance is 400, what score represents the
16th percentile?
A.470
B.480
C.490
D. Impossible to determine from what is given
E. None of the above
4. What advantage do T-scores and z-scores have
over raw scores?
A. There is no real advantage, but people use
them because they are “standard” in nature.
B. They can be added because of their standardized characteristics.
C. The mean is 50 and the standard deviation is
equal to 1 for each.
D. The values are controllable.
E. They represent the normal curve, whereas
raw scores do not.
7. What is the percentile for a raw score of 82?
8. Karen’s T-score was 65. What is her z-score?
A.–2.0
B.–1.5
C.–0.5
D. Need more information
E. None of the above
TABLE
4.1
Grouped frequency distribution.
INTERVAL
FREQUENCY
PERCENTILE
148–152
5
100.0
143–147
7
95.0
138–142
18
88.0
133–137
20
70.0
128–132
10
50.0
123–127
15
40.0
118–122
9
25.0
113–117
8
16.0
108–112
6
8.0
103–107
2
2.0
Answer problems 9 and 10 by referring to the grouped
frequency distribution in Table 4.1.
9.
In which interval would you probably find a per-
son one standard deviation below the mean?
A.123–127
B.118–122
C.113–117
D.108–112
E. It is impossible to determine.
10. In which interval is a T-score of 60 located?
A.143–147
B.138–142
C.133–137
D.128–132
E. None of the above
11. Stanines are standard scores that have a mean
of 5 and a standard deviation of 2. Suppose
Ralph scored 75 on a spelling test that had a
mean of 50 and a standard deviation of 12.5. What
is Ralph’s stanine score?
A.2
B.9
C.70
D.80
12. What is the standard deviation of the weight
scores, given the information below? Assume
that a student who is 70 in tall and weighs 155
lbs will be at the same percentile point in each
distribution (that is, assume normality).
Height
_
X = 64 in
s = 4 in
A. 1.5 lbs
B. 6.0 lbs
C. 10.0 lbs
D. 15.0 lbs
Weight
_
X = 140 lbs
s = ? lbs