Question 1

Given the numbers 1, 2, and 3, the standard deviation is

Accepted Answer

A)  0 
B)  1 
C)  0.667 
D)  the square of the variance 
A)  0 
B)  1 
C)  0.667 
D)  the square of the variance B

Question 2

A boxplot is better than a statistic such as the mean when your purpose is

Accepted Answer

A)  to describe the central tendency of a population. 
B)  to describe the variability of a population. 
C)  to understand what a distribution of data looks like. 
D)  It is only worthwhile if you care only about medians. 
A)  to describe the central tendency of a population. 
B)  to describe the variability of a population. 
C)  to understand what a distribution of data looks like. 
D)  It is only worthwhile if you care only about medians. C

Question 3

The interquartile range

Accepted Answer

A)  is the 50th percentile score in a data set. 
B)  contains as few as 25% of scores or as many as 75% of scores in a data set 
C)  contains the middle 50% of scores in a data set. 
D)  is the same as the range. 
A)  is the 50th percentile score in a data set. 
B)  contains as few as 25% of scores or as many as 75% of scores in a data set 
C)  contains the middle 50% of scores in a data set. 
D)  is the same as the range. C

Question 4

When calculating the standard deviation we divide by N -1 rather than N because the result is

Accepted Answer

A)  smaller. 
B)  less biased. 
C)  easier to interpret. 
D)  equal to the population mean. 
A)  smaller. 
B)  less biased. 
C)  easier to interpret. 
D)  equal to the population mean.

Question 5

Which of the following is NOT a method of describing data that reduces the role of outliers on the measurement of a data set's variability?

Accepted Answer

A)  interquartile range 
B)  boxplot 
C)  range 
D)  trimmed statistics 
A)  interquartile range 
B)  boxplot 
C)  range 
D)  trimmed statistics

Question 6

Trimmed statistics are calculated based on the entire sample.

Accepted Answer

A) True 
 B)False

Question 7

Measures of variability refer to the dispersion of data around the mean or the center.

Accepted Answer

A) True 
 B)False

Question 8

The problem with measuring dispersion by merely averaging all the deviations between each score and the overall mean is that

Accepted Answer

A)  positive and negative deviations will balance out. 
B)  squared values make intuitive interpretation difficult. 
C)  dividing by (N-1) gives a biased statistic. 
D)  There are no problems with measuring dispersion this way. 
A)  positive and negative deviations will balance out. 
B)  squared values make intuitive interpretation difficult. 
C)  dividing by (N-1) gives a biased statistic. 
D)  There are no problems with measuring dispersion this way.

Question 9

People in the stock market refer to a measure called the "standard deviation," although it is calculated somewhat differently from the one discussed here. It is a good guess that this measure refers to

Accepted Answer

A)  the riskiness of the stock. 
B)  the value of the stock. 
C)  how much the stock price is likely to fluctuate. 
D)  how much money you are likely to earn from buying that stock. 
A)  the riskiness of the stock. 
B)  the value of the stock. 
C)  how much the stock price is likely to fluctuate. 
D)  how much money you are likely to earn from buying that stock.

Question 10

Answer the next two questions based on the following box-plot. 
   
The median of this distribution is 16.

Accepted Answer

A) True 
 B)False

Question 11

Which of the following sets of data is likely to have the smallest standard deviation?

Accepted Answer

A)  the distribution of SAT scores for students from your high school 
B)  the distribution of heights of students in an elementary school 
C)  the grade point averages of students from your high school's honors biology class 
D)  the amount that you and your friends pay for college tuition 
A)  the distribution of SAT scores for students from your high school 
B)  the distribution of heights of students in an elementary school 
C)  the grade point averages of students from your high school's honors biology class 
D)  the amount that you and your friends pay for college tuition

Question 12

Compare the distribution of exam scores for students who did and did not read the textbook prior to taking the exam. Discuss measures of variability and of central tendency.

Accepted Answer

On average, students who read the text s

Question 13

Which of the following is NOT a measure of variability?

Accepted Answer

A)  the density 
B)  the range 
C)  the standard deviation 
D)  the interquartile range 
A)  the density 
B)  the range 
C)  the standard deviation 
D)  the interquartile range

Question 14

Given the following distribution, which would be the least useful measure of central tendency? Explain your answer.

Accepted Answer

The mean would be least useful

Question 15

-Based on the same data, calculate: 
a. The median location 
b. The median 
c. The hinge location 
d. The upper hinge 
e. The lower hinge 
f. H spread 
g. Lower fence 
h. Upper fence 
i. Lower adjacent value 
j. Upper adjacent value

Accepted Answer

a. median location = 10.5 
b. median = 2

Question 16

If we multiply a set of data by a constant, such as converting feet to inches, we will

Accepted Answer

A)  leave the mean and variance unaffected. 
B)  multiply the mean and the standard deviation by the constant. 
C)  multiply the mean by the constant but leave the standard deviation unchanged. 
D)  leave the mean unchanged but alter the standard deviation. 
A)  leave the mean and variance unaffected. 
B)  multiply the mean and the standard deviation by the constant. 
C)  multiply the mean by the constant but leave the standard deviation unchanged. 
D)  leave the mean unchanged but alter the standard deviation.

Question 17

If the average adult male in the United States is 5' 9" tall, and the standard deviation for height is 2", approximately how many adult males would you expect to be between 5' 7" and 5'11" tall?

Accepted Answer

A)  50% of them 
B)  66.7% of them 
C)  75% of them 
D)  90% of them 
A)  50% of them 
B)  66.7% of them 
C)  75% of them 
D)  90% of them

Question 18

You would obtain a negative value for the variance if

Accepted Answer

A)  all observations were at the mean. 
B)  the distribution is very negatively skewed. 
C)  the distribution if positively skewed. 
D)  you would never obtain a negative variance. 
A)  all observations were at the mean. 
B)  the distribution is very negatively skewed. 
C)  the distribution if positively skewed. 
D)  you would never obtain a negative variance.

Question 19

An outlier

Accepted Answer

A)  can be an extreme score. 
B)  can be an error that snuck into the data. 
C)  will never have a large influence on many measures of variability. 
D)  both a and b 
A)  can be an extreme score. 
B)  can be an error that snuck into the data. 
C)  will never have a large influence on many measures of variability. 
D)  both a and b

Question 20

A sample of 20 families reported how many children they have. Answer the following questions based on the summary table below. 
   
a) What is the range? 
b. What is the variance? 
c. What is the standard deviation?

Accepted Answer

a. range = 4 
b. var

Exam 5: Measures of Variability

Given the numbers 1, 2, and 3, the standard deviation is

A boxplot is better than a statistic such as the mean when your purpose is

The interquartile range

When calculating the standard deviation we divide by N -1 rather than N because the result is

Which of the following is NOT a method of describing data that reduces the role of outliers on the measurement of a data set's variability?

Trimmed statistics are calculated based on the entire sample.

Measures of variability refer to the dispersion of data around the mean or the center.

The problem with measuring dispersion by merely averaging all the deviations between each score and the overall mean is that

People in the stock market refer to a measure called the "standard deviation," although it is calculated somewhat differently from the one discussed here. It is a good guess that this measure refers to

Answer the next two questions based on the following box-plot. The median of this distribution is 16.

Which of the following sets of data is likely to have the smallest standard deviation?

Compare the distribution of exam scores for students who did and did not read the textbook prior to taking the exam. Discuss measures of variability and of central tendency.

Which of the following is NOT a measure of variability?

Given the following distribution, which would be the least useful measure of central tendency? Explain your answer.

-Based on the same data, calculate: a. The median location b. The median c. The hinge location d. The upper hinge e. The lower hinge f. H spread g. Lower fence h. Upper fence i. Lower adjacent value j. Upper adjacent value

If we multiply a set of data by a constant, such as converting feet to inches, we will

If the average adult male in the United States is 5' 9" tall, and the standard deviation for height is 2", approximately how many adult males would you expect to be between 5' 7" and 5'11" tall?

You would obtain a negative value for the variance if

An outlier

A sample of 20 families reported how many children they have. Answer the following questions based on the summary table below. a) What is the range? b. What is the variance? c. What is the standard deviation?

Introduction

Basic Concepts

Displaying Data

Measures of Central Tendency

The Normal Distribution

Basic Concepts of Probability

Sampling Distributions and Hypothesis Testing

Correlation

Regression

Multiple Regression

Hypothesis Tests Applied to Means: One Sample

Hypothesis Tests Applied to Means: Two Related Samples

Hypothesis Tests Applied to Means: Two Independent Samples

Power

One-Way Analysis of Variance

Factorial Analysis of Variance

Repeated-Measures Analysis of Variance

Chi-Square

Nonparametric and Resampling Statistical Tests

Meta-Analysis

Filters