Question 1

A sample average can be used to estimate a population average with greater precision if the sample is

Accepted Answer

A)  large. 
B)  a skewed distribution. 
C)  highly variable. 
D)  vivid and memorable.

Question 2

If two sets of scores are negatively correlated, it means that

Accepted Answer

A)  as one set of scores increases, the other decreases. 
B)  as one set of scores increases, the other increases. 
C)  there is only a weak relationship between the sets of scores. 
D)  there is no relationship at all between the sets of scores.

Question 3

Kiska used a scatterplot to display the relationship between college students' self-esteem and their feelings of depression. The points on the scatterplot are most likely clustered in a pattern that

Accepted Answer

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

Question 4

Displaying data in a scatterplot can help us see the extent to which two variables are

Accepted Answer

A)  random samples. 
B)  operationally defined. 
C)  correlated. 
D)  replications.

Question 5

Measures of central tendency are most useful for

Accepted Answer

A)  random sampling. 
B)  summarizing data. 
C)  preventing skewed distributions. 
D)  constructing scatterplots.

Question 6

A normal curve would be LEAST likely to characterize a large random sample of

Accepted Answer

A)  body weights. 
B)  intelligence scores. 
C)  family incomes. 
D)  professional baseball batting averages.

Question 7

Which of the following correlation coefficients indicates the strongest relationship between two variables?

Accepted Answer

A)  -.73 
B)  +.66 
C)  0.00 
D)  -.50

Question 8

Which statistical phenomenon refers to the tendency for extraordinary or unusual events to be followed by more ordinary events?

Accepted Answer

A)  the standard deviation 
B)  the normal curve 
C)  regression toward the mean 
D)  illusory correlation

Question 9

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 85 and 115?

Accepted Answer

A)  34 
B)  50 
C)  68 
D)  95

Question 10

Regression toward the mean is the

Accepted Answer

A)  tendency for unusual scores to fall back toward a distribution's average. 
B)  basis for all tests of statistical significance. 
C)  reason the range is a more accurate measure of variation than the standard deviation. 
D)  reason the standard deviation is a more accurate measure of variation than the range.

Question 11

Seven members of a girls' club reported the following individual earnings from their sale of raffle tickets: $5, $9, $4, $11, $6, $4, and $3. In this distribution of individual earnings, the

Accepted Answer

A)  median is greater than the mean and greater than the mode. 
B)  median is less than the mean and less than the mode. 
C)  median is greater than the mean and less than the mode. 
D)  median is less than the mean and greater than the mode.

Question 12

Gamblers who blow on their dice "for luck" are victims of

Accepted Answer

A)  regression toward the mean. 
B)  the illusion of control. 
C)  hindsight bias. 
D)  the fundamental attribution error.

Question 13

In the following distribution, the mean is ________ the mode and ________ the median: 4, 6, 1, 4, 5.

Accepted Answer

A)  less than; less than 
B)  less than; greater than 
C)  equal to; equal to 
D)  greater than; equal to

Question 14

Although Dominick's psychology class is sometimes longer or shorter than usual, on average each class is 50 minutes. If the lengths of these classes form a normal curve, which statistic would enable Dominick to estimate the probability that any single class will last somewhere between 47 and 53 minutes?

Accepted Answer

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

Question 15

Differences between two samples are LEAST likely to be statistically significant if the samples are ________ and the standard deviations of the samples are ________.

Accepted Answer

A)  small; small 
B)  large; large 
C)  small; large 
D)  large; small

Question 16

Approximately what percentage of the cases represented by the normal curve fall between -1 and +1 standard deviations from the mean?

Accepted Answer

A)  16 
B)  34 
C)  68 
D)  95

Question 17

Why is the median at times a better measure of central tendency than the mean?

Accepted Answer

A)  It is more sensitive to extreme scores. 
B)  It is less sensitive to extreme scores. 
C)  It is based on more of the scores in the distribution than the mean. 
D)  It is the arithmetic average.

Question 18

Which of the following correlation coefficients expresses the weakest degree of relationship between two variables?

Accepted Answer

A)  -0.12 
B)  -0.99 
C)  +0.25 
D)  -0.50

Question 19

Six different high school students spent $10, $13, $2, $12, $13, and $4, respectively, on entertainment. The mode of this group's entertainment expenditures is

Accepted Answer

A)  $9. 
B)  $11. 
C)  $12. 
D)  $13.

Question 20

If the points on a scatterplot are clustered in a pattern that extends from the upper left to the lower right, this would suggest that the two variables depicted are

Accepted Answer

A)  normally distributed. 
B)  positively correlated. 
C)  negatively correlated. 
D)  not correlated.

Exam 16: Statistical Reasoning in Everyday Life