Question 1

Stefan has collected a large amount of data in a study designed to test the effectiveness of a new drug meant to slow the progression of Alzheimer's disease.To test whether the drug was effective in a group of participants who received it,in comparison to a group that received a placebo,which type of statistics should Stefan use?

Accepted Answer

A)  descriptive statistics 
B)  frequency statistics 
C)  histogram statistics 
D)  inferential statistics

Question 2

The standard deviation

Accepted Answer

A)  indicates the average difference between each score in a group and the mean for that group of scores. 
B)  reveals the degree of skew for a group of scores. 
C)  is sensitive to scores at the extremes of a distribution of scores. 
D)  is used to determine whether a data set is positively or negatively skewed.

Question 3

In a strongly skewed distribution,the best indicator of central tendency is usually the

Accepted Answer

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

Question 4

The three measures of central tendency tend to converge in a

Accepted Answer

A)  symmetrical distribution. 
B)  asymmetrical distribution. 
C)  positively skewed distribution. 
D)  negatively skewed distribution.

Question 5

The symmetric,bell shaped curve that represents the pattern in which many human characteristics are dispersed in the population is known as a

Accepted Answer

A)  scatter plot. 
B)  normal distribution. 
C)  frequency polygon. 
D)  histogram.

Question 6

The two major strengths of the empirical approach are

Accepted Answer

A)  it reveals facts and truths. 
B)  there is a chance one will discover errors in thinking. 
C)  its precision and intolerance for error. 
D)  there is no chance one's conclusion will be wrong.

Question 7

Dr.Kleiman gives an exam where most of the students receive failing grades and only a few students receive high scores.When the exam scores are plotted,the distribution will be

Accepted Answer

A)  positively skewed. 
B)  negatively skewed. 
C)  symmetrical. 
D)  impossible to predict without more information.

Question 8

Before you construct a histogram you need to

Accepted Answer

A)  calculate an inferential statistic. 
B)  calculate a correlation. 
C)  create a frequency distribution. 
D)  create a series of percentile ranks.

Question 9

The index of the amount of variability in a set of data is known as the

Accepted Answer

A)  mean. 
B)  standard deviation. 
C)  median. 
D)  frequency distribution.

Question 10

In a normal distribution,most scores fall near the ____ of the distribution,and the number of scores gradually ____ as one moves away from the mean.

Accepted Answer

A)  low end; increases 
B)  center; declines 
C)  center; increases 
D)  high end; declines

Question 11

When a distribution of scores is not symmetrical and many scores pile up at the low end of the scale,the distribution is a

Accepted Answer

A)  positively skewed distribution. 
B)  negatively skewed distribution. 
C)  significant distribution. 
D)  normal distribution.

Question 12

Generally,the MINIMUM requirement for statistical significance is that there is less than ____ that the observed results are due to chance.

Accepted Answer

A)  1 chance in 1000 
B)  5 chances in 100 
C)  20 chances in 100 
D)  50 chances in 100

Question 13

A professor who has two sections of the same course gives an exam.Both classes have the same mean score on the exam.However,in Class A most students scored relatively close to the mean,while in Class B many students scored either much higher or much lower than the mean.Which statement best describes the distribution of grades for the two classes?

Accepted Answer

A)  the standard deviation will be the same for the two classes 
B)  the standard deviation will be larger for Class A than for Class B 
C)  the standard deviation will be smaller for Class A than for Class B 
D)  not enough information is provided to draw any conclusion regarding the standard deviation

Question 14

You find a correlation of .44 between a measure of subjects' extraversion and their reports of how many people they have dated in the last two years.This finding means that

Accepted Answer

A)  44 percent of extraverts date a lot. 
B)  extraversion accounts for 44 percent of the variation in the amount of subjects' dating. 
C)  high extraversion is associated with infrequent dating. 
D)  high extraversion is associated with more frequent dating.

Question 15

High scores on variable X are associated with high scores on variable Y,and low scores on variable X are associated with low scores on variable Y.Hence,the correlation between variables X and Y will be

Accepted Answer

A)  negative. 
B)  positive. 
C)  zero. 
D)  spurious.

Question 16

The square root of Sd²/n is the formula for the

Accepted Answer

A)  central tendency. 
B)  standard deviation. 
C)  frequency distribution. 
D)  correlation coefficient.

Question 17

Al and Carmen have the same bowling average,but Al is much more erratic than Carmen.If we compute the standard deviations for their respective distributions of bowling scores,which of the following will be true?

Accepted Answer

A)  Al's standard deviation will be higher than Carmen's. 
B)  Marilyn's standard deviation will be higher than Al's. 
C)  Both standard deviations will be the same. 
D)  Al's scores will be symmetrical while Carmen's will be positively skewed.

Question 18

Kurt has collected data on the relationship between the number of hours the employees at a large number of corporate headquarters spend working on their computers and the profits of the corporations.His scatter diagram of the data shows it clusters near a line running from the bottom left corner to the top right corner

Accepted Answer

A)  variable. 
B)  zero. 
C)  positive. 
D)  negative.

Question 19

In the formula for the standard deviation,the symbol S stands for

Accepted Answer

A)  summation. 
B)  sum of the squares. 
C)  deviation from the mean. 
D)  deviation from the normal distribution.

Question 20

Professor Latimore gives an exam that turns out to be exceptionally easy and everyone does well,yielding a

Accepted Answer

A)  normal distribution. 
B)  negatively skewed distribution. 
C)  positively skewed distribution. 
D)  bimodal distribution.

Exam 17: Statistical Methods