Question

1. a student’s test score is at the 42nd percentile. this means that the student has______ (2007 ap psychology exam)

a. received the 42nd highest score
b. answered 86% of the test correctly
c. scored the same as 42% of her fellow students
d. scored the same as or higher than 42% of her fellow students.
e. scored the same as or higher than 58% of her fellow students.

1. which of the following correlation coefficients most likely represents the relationship between length of sleep deprivation and level of alertness? (2007 ap psychology exam)

a. 1.35
b. 0.85
c. 0.01
d. -0.4
e. -1.25

1. for a language test with a normally distributed scores, the mean was 70 and the standard deviation was 10. approximately what percentage of test takers scored 60 and above? (2004 ap psychology exam)

a. 16
b. 34
c. 68
d. 84
e. 95

1. which of the following sets of scores has the greatest standard deviation? (2008 ap psychology practice exam)

a. 5,7,9,12
b. 2,7,9,12
c. 25,27,29,32
d. 50,51,52,53
e. 100,101,101,102,103
10.
set a set b
60 60
56 41
58 76
62 35
61 65
59 50
which of the following is true of the two sets of scores to the left? (2008 ap psychology practice exam)
a. set a has a larger standard deviation
b. set b has a larger standard deviation
c. the range is the same for both distributions
d. set a has a lower median score than set b
e. the mean score is the same for both distributions

Explanation:

1. By definition, the nth percentile means scoring the same as or higher than n% of the group.
2. As sleep - deprivation increases, alertness decreases, indicating a negative correlation. Correlation coefficients range from - 1 to 1, so -0.4 is a reasonable negative correlation for this relationship.
3. A score of 60 is one standard - deviation below the mean in a normal distribution. Approximately 16% of scores are below one standard - deviation below the mean, so about 84% are 60 and above.
4. Standard deviation measures the spread of data. The set 5,7,9,12 has the greatest spread among the given sets.
5. Set B has more extreme values relative to its mean compared to Set A, so it has a larger standard deviation.

Answer:

1. D. Scored the same as or higher than 42% of her fellow students.
2. D. -0.4
3. D. 84
4. A. 5,7,9,12
5. B. Set B has a larger standard deviation