Deck 4: The Normal Curve and Standard Scores

Question 1

For which of the following measurements would you change the sign of the numerator in the z-score equation?

A) Time to run the 50-yard dash
B) Time to exhaustion on a treadmill
C) Vertical jump scores
D) Distance the shot put is thrown

Answer 1

A

Question 2

Approximately what percentile is associated with a score located one standard deviation below the mean in a normal distribution?

A) 40
B) 35
C) 22
D) 16
E) Not possible to determine from information given.

Answer 2

D

Question 3

What is the mean of a normal distribution with a standard deviation of 3, if a score of 50 in this distribution is equal to a z-score of 1.0?

A) 16.7
B) 47
C) 50
D) Need the standard error of the mean to determine.

Answer 3

B

Question 4

On which test did Shawn do best?

A) Test one: Shawn scored exactly at the mean.
B) Test two: Shawn's score was a z-score of -1.2.
C) Test three: Shawn's score was a T-score of 47.
D) Test four: Shawn's score was a percentile of 38.

Question 5

Which of the following is a discrete variable?

A) Maximum oxygen consumption
B) Percent fat
C) Time for mile run
D) Score on this examination

Question 6

Which of the following is a continuous variable?

A) Sit-ups
B) Number of students in a class
C) Body weight
D) Number of bathtubs in Boulder, Colorado

Question 7

Bob's score of 40 on a statistics test was reported to be at the 60th percentile. Fifty students took the test. How many students scored lower than Bob?

A) 20
B) 30
C) 40
D) 50

Question 8

Suppose a normal distribution of scores has a mean of 200 and a standard deviation of 20. What is the score in the distribution below which 97.5% of the scores would fall?

A) 210.0
B) 220.0
C) 232.8
D) 239.2

Question 9

What T-score is equivalent to a z-score of -1.5?

A) 65
B) 52.94
C) 51.5
D) 35

Question 10

SAT scores are normally distributed with a mean of 500 and a standard deviation of 100. A student's SAT score was at the 36th percentile. What was her raw score? (Round to the nearest whole number.)

A) 484
B) 464
C) 434
D) 392
E) None of the above

Question 11

What is the percentile associated with a T-score of 43?

A) 48.20
B) 33.20
C) 25.80
D) 24.20
E) None of the above

Question 12

The mean score on a test is 80, and the standard deviation is 20 points. What percentage of people scored 75 or less? (Round to the nearest whole number.)

A) 10
B) 40
C) 43
D) 60
E) None of the above

Question 13

If the mean of a distribution is 80, and the standard deviation is 10, which of the following does not belong with the others?

A) percentile= 38.69
B) raw score= 67.9
C) T-score = 37.9
D) z-score= -1.21

Question 14

If the variance is 121, and the 16th percentile is 988, which of the following is probably the mean?

A) 995
B) 999
C) 1000
D) 1005
E) 1009

Question 15

Given that the mean of a distribution is 80, the standard deviation is 10, the variance is 100, and number of people who took the test is 200, which person scored the highest?

A) John, whose z-score is -1.34.
B) Mike, who had a T-score of 36.
C) Pete, whose raw score was 65.
D) Karen, whose percentile is the 30th.
E) It is impossible to determine.

Question 16

What is the z-score corresponding to the 39th percentile?

A) -.23
B) -.28
C) -.67
D) -1.23
E) None of the above

Question 17

Suppose you want to grade a class on the "normal curve." What characteristic of the distribution are you most concerned about?

A) The typical score earned
B) The 16th percentile
C) The class mean
D) The degree of skewness in the class distribution
E) The 50th percentile

Question 18

In a normal distribution with a mean of 50 and a standard deviation of 7.5, what is the value of the mode?

A) 42.5
B) 50
C) 57.5
D) Not possible to determine from the information given.

Question 19

If a distribution of scores is known to be normal and has a mean of 60 and a standard deviation of 7.33, what range of scores would include 99.74% of the scores?

A) 53-67
B) 45-75
C) 40-80
D) 38-82

Question 20

Suppose a normal distribution has a standard deviation of 15. Judy has a raw score of 120 and a z-score of .5. What is the mean of the distribution?

A) -127.5
B) -112.5
C) +112.5
D) +127.5

Question 21

For a normal distribution, with a mean of 10, if approximately 16% of the observations lie above a score of 13, what is the VARIANCE of the distribution?

A) .3
B) 9
C) 13
D) 19

Question 22

Which of the following is a discrete variable?

A) Temperature
B) Time
C) Number of cars in the parking lot
D) Body weight

Question 23

What z-score is associated with the 80th percentile in a normal distribution?

A) -.84
B) -.52
C) +.52
D) +.84

Question 24

In a normal distribution, what percentage of the scores are located between z values of-1.2 and +1.5?

A) 12
B) 82
C) 88
D) 93

Question 25

Assume GRE scores are normally distributed with a mean of 500 and a standard deviation of 100. A student's verbal GRE score is 470. What is the percentile rank of this score?

A) 48
B) -.3
C) 30
D) 38

Question 26

$\begin{array}{lcl}& \text {Boys } & \text { Girls } \\\\\bar{X}= & 100 & 120 \\s= & 20 & 10\end{array}$

-Using the data above, a raw score of 115 for the boys has the same percentile as what raw score for the girls?

A) 129.5
B) 127.5
C) 123.5
D) 121.5
E) None of the above