Question 1
0.5 out of 0.5 points
If a distribution has a mean of 50 and a standard deviation of 25, how many standard
deviations is 0 from the mean?
Selected Answer:
A.
-2
Question 2
0.5 out of 0.5 points
What type of standard score has M = 0 and SD = 1?
Selected Answer:
B.
z score
Question 3
0.5 out of 0.5 points
In a distribution with a mean of 100 and a standard deviation of 15, what is the probability
that a score will be 115 or higher?
Selected Answer:
B.
16%
Question 4
0.5 out of 0.5 points
A score that is 2 1/2 standard deviations below the mean would have a z-score of:
Selected Answer:
D.
-2.5
Question 5
0.5 out of 0.5 points
Standard scores are raw scores which have been adjusted for the particular mean and standard
deviation of the distribution from which they are derived.
Selected Answer:
True
Question 6
0 out of 0.5 points
What is the area within .7 standard deviations of the mean? Use Appendix A (
z
Distribution)
to answer this question.
Selected Answer:
48%
Response
Feedback:
This is twice the area between the mean and
z
= +0.7 from the area under the
normal curve. Choice B is correct. Choices A, C, and D represent errors in
logic or calculation.
Question 7
0.5 out of 0.5 points
Sarah and her brother Shaun go to the same high school. Sarah is a senior and Shaun is a

junior. Sarah’s English final exam raw score was 75, and her
z
score was –0.83. Shaun’s
English final exam raw score was 75, and his
z
score was +.40. Which of the following
conclusions must be true?
Selected Answer:
The mean of the senior exam was higher than the mean of the junior
exam.
Question 8
0.5 out of 0.5 points
If a z score of 1.65 included 45% of the area under the normal curve from the mean, what
percent remains above 1.65 on the X axis?
Selected Answer:
B.
5%
Question 9
0.5 out of 0.5 points
What is the area under the normal curve between
z
= 0.0 and
z
= –2.9? Use Appendix A
(
z
Distribution) to answer this question.
Selected Answer:
49.81%
Question 10
0.5 out of 0.5 points
Aretha has a score of 35 on an anxiety inventory, in which higher scores mean more anxiety.
The mean for scores on this inventory is 50. Should she consult a psychologist about her level
of anxiety?
Selected Answer:
More information is needed to answer the question
Question 11
0.5 out of 0.5 points
The percentages or areas under the normal curve can be interpreted as probabilities.
Selected Answer:
True
Question 12
0 out of 0.5 points
Cesar’s
z
score is +2.0. Rhonda’s
z
score is +1.0. Cesar tells Rhonda that his score shows he
outscored twice as many people as she did. Is he correct?
Selected Answer:
No, Cesar’s score is only somewhat better than Rhonda’s.
Response
Feedback:
Normal curve theory supports the reasoning in Choice B. The reasoning is
faulty in Choices A and C because 16% outscore Rhonda, compared with 2%
outscoring Cesar. The reasoning is faulty in choice D because
z
scores are
interval level measures that lack an absolute zero point.

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- Summer '13
- Staff
- Statistics, Standard Deviation