Question 1

Which of the following is the measure of central tendency that would be most affected by a few extreme scores?

Accepted Answer

A)  mean 
B)  range 
C)  median 
D)  mode

Question 2

Statistical significance refers to whether research

Accepted Answer

A)  variables are causally related. 
B)  participants were randomly assigned to conditions. 
C)  findings are due to chance variations. 
D)  results add support to previous findings.

Question 3

The mode of a distribution of scores is the

Accepted Answer

A)  score exceeded by 50 percent of all the scores. 
B)  most frequently occurring score. 
C)  arithmetic average of all the scores. 
D)  difference between the highest and lowest scores.

Question 4

The range is

Accepted Answer

A)  the difference between the highest and lowest scores in a distribution. 
B)  the most commonly used measure of variation. 
C)  the average deviation of scores from the mean. 
D)  the most frequently occurring score in a distribution of scores.

Question 5

After sports magazines give cover-story attention to the outstanding performance of an athlete, the individual often suffers a real decline in performance. This may be at least partially explained in terms of

Accepted Answer

A)  illusory correlation. 
B)  the illusion of control. 
C)  the random sampling effect. 
D)  regression toward the mean.

Question 6

To compare verbal intelligence at different age levels, researchers tested and retested a group of children from the time they were 2 until they reached the age of 20. The researcher were clearly using a

Accepted Answer

A)  longitudinal study. 
B)  correlation coefficient. 
C)  cross-sectional study. 
D)  regression toward the mean.

Question 7

If IQ scores are normally distributed, having a mean of 100 and a standard deviation of 15, approximately what percentage of people have IQ scores between 55 and 145?

Accepted Answer

A)  34 
B)  68 
C)  95 
D)  100

Question 8

The maximum height of a normal curve corresponds to the ________ of a normal distribution.

Accepted Answer

A)  range 
B)  mean 
C)  standard deviation 
D)  statistical significance

Question 9

If a positive correlation between two sets of scores is displayed as a scatterplot, the points are clustered in a pattern that

Accepted Answer

A)  resembles a bell-shaped curve. 
B)  extends from the lower left to the upper right of the graph. 
C)  resembles a U-shaped curve. 
D)  extends from the upper left to the lower right of the graph.

Question 10

The difference between the highest and lowest scores in a distribution is the

Accepted Answer

A)  mean. 
B)  range. 
C)  median. 
D)  standard deviation.

Question 11

Which measure of variation is affected most by a few extreme scores?

Accepted Answer

A)  standard deviation 
B)  mean 
C)  median 
D)  range

Question 12

On a 10-item test, three students in Professor Hsin's advanced chemistry seminar received scores of 2, 5, and 8, respectively. For this distribution of test scores, the standard deviation is equal to the square root of

Accepted Answer

A) 4. 
B) 5. 
C) 6. 
D) 9

Question 13

The most familiar measure of central tendency is the

Accepted Answer

A)  mode. 
B)  mean. 
C)  median. 
D)  standard deviation.

Question 14

When Mr. Adams calculated his students' algebra test scores, he noticed that two students had extremely low scores. Which measure of central tendency is affected most by the scores of these two students?

Accepted Answer

A)  mean 
B)  standard deviation 
C)  mode 
D)  median

Question 15

What is the mean of the following distribution of scores: 2, 3, 7, 6, 1, 4, 9, 5, 8, 2?

Accepted Answer

A)  5 
B)  4 
C)  4.7 
D)  3.7

Question 16

During the past year, Zara and Ivan each read 2 books, but George read 9, Ali read 12, and Marsha read 25. The median number of books read by these individuals was

Accepted Answer

A)  2 
B)  10 
C)  12 
D)  9

Question 17

Which of the following statistical measures is most helpful for indicating the extent to which people's happiness predicts the number of friends they have?

Accepted Answer

A)  standard deviation 
B)  median 
C)  mean 
D)  correlation coefficient

Question 18

The precision with which a sample average approximates a population average increases as

Accepted Answer

A)  the standard deviation of the sample increases. 
B)  the standard deviation of the sample decreases. 
C)  the mean of the sample increases. 
D)  the mean of the sample decreases.

Question 19

As the size of a sample ________, the size of the standard deviation is most likely to ________.

Accepted Answer

A)  increases; increase 
B)  increases; decrease 
C)  decreases; remain the same 
D)  increases or decreases; remain the same

Question 20

In a normal distribution, what percentage of scores fall between -1 and +1 standard deviation units of the mean?

Accepted Answer

A)  50 percent 
B)  68 percent 
C)  95 percent 
D)  99.7 percent

Exam 16: Statistical Reasoning in Everyday Life