Question 1

In a boxplot the width of the box encompasses

Accepted Answer

A)  all of the observed values. 
B)  all but the most extreme values. 
C)  approximately 50% of the observed values. 
D)  the center-most 10% of the values. 
A)  all of the observed values. 
B)  all but the most extreme values. 
C)  approximately 50% of the observed values. 
D)  the center-most 10% of the values.

Question 2

The median is a measure of variability.

Accepted Answer

A) True 
 B)False

Question 3

If we eliminate the top and bottom 25% of the data and take the range of what remains we have the

Accepted Answer

A)  range. 
B)  adjusted range. 
C)  interquartile range. 
D)  quartile variance. 
A)  range. 
B)  adjusted range. 
C)  interquartile range. 
D)  quartile variance.

Question 4

Answer the following questions based on this distribution of exam scores. 
   
a. What is the median? 
b. Are there outliers? 
c. Does the distribution seem skewed?   If so, is it positively, or negatively skewed?

Accepted Answer

a. median = 81 (estimate aroun

Question 5

A "hinge" is another word for

Accepted Answer

A)  the median. 
B)  a quartile. 
C)  the range. 
D)  boundary. 
A)  the median. 
B)  a quartile. 
C)  the range. 
D)  boundary.

Question 6

The sample variance is a biased statistic.

Accepted Answer

A) True 
 B)False

Question 7

Data points at the extremes of the distribution have

Accepted Answer

A)  little effect on the variance. 
B)  more effect on the variance than scores at the center of the distribution. 
C)  are undoubtedly incorrect. 
D)  distort the usefulness of the median. 
A)  little effect on the variance. 
B)  more effect on the variance than scores at the center of the distribution. 
C)  are undoubtedly incorrect. 
D)  distort the usefulness of the median.

Question 8

Of all of the measures of variability, the standard deviation is most susceptible to distortion due to outliers.

Accepted Answer

A) True 
 B)False

Question 9

The vertical line in the center of a box plot

Accepted Answer

A)  represents the sample mean. 
B)  represents the sample median. 
C)  serves to anchor the box. 
D)  can represent anything you want it to. 
A)  represents the sample mean. 
B)  represents the sample median. 
C)  serves to anchor the box. 
D)  can represent anything you want it to.

Question 10

We normally compute the variance using N - 1 in the denominator because

Accepted Answer

A)  it is easier that way. 
B)  it leads to an unbiased estimate of the sample variance. 
C)  it leads to an unbiased estimate of the population variance. 
D)  it overestimates that population variance. 
A)  it is easier that way. 
B)  it leads to an unbiased estimate of the sample variance. 
C)  it leads to an unbiased estimate of the population variance. 
D)  it overestimates that population variance.

Question 11

Construct two small sets of data that have the same mean, but a different standard deviation.

Accepted Answer

Possible examples include: 
4,

Question 12

The range is

Accepted Answer

A)  the difference between the inner fences. 
B)  the H-spread. 
C)  not influenced very much by outliers. 
D)  the difference between the highest and lowest score. 
A)  the difference between the inner fences. 
B)  the H-spread. 
C)  not influenced very much by outliers. 
D)  the difference between the highest and lowest score.

Question 13

The population variance is

Accepted Answer

A)  an estimate of the sample variance. 
B)  calculated exactly like the sample variance. 
C)  a biased estimate. 
D)  usually an unknown that we try to estimate. 
A)  an estimate of the sample variance. 
B)  calculated exactly like the sample variance. 
C)  a biased estimate. 
D)  usually an unknown that we try to estimate.

Question 14

If I continue to draw observations from a population and recalculate the mean each time I add an observation, the mean will approach _______ as the sample size increases.

Accepted Answer

A)  its expected value 
B)  the true population mean 
C)  the median of the population if the population is symmetric 
D)  all of the above 
A)  its expected value 
B)  the true population mean 
C)  the median of the population if the population is symmetric 
D)  all of the above

Question 15

The difference between the lowest to the highest score in a distribution is the range.

Accepted Answer

A) True 
 B)False

Question 16

The equation
  is used to calculate the

Accepted Answer

A)  median. 
B)  hinge location. 
C)  outer fence. 
D)  inner fences. 
A)  median. 
B)  hinge location. 
C)  outer fence. 
D)  inner fences.

Question 17

We generally like the standard deviation when we are trying to describe a sample of data because

Accepted Answer

A)  it is larger than the variance. 
B)  it allows for more intuitive interpretation with respect to the data than does the variance. 
C)  it is less biased than the variance. 
D)  all of the above 
A)  it is larger than the variance. 
B)  it allows for more intuitive interpretation with respect to the data than does the variance. 
C)  it is less biased than the variance. 
D)  all of the above

Question 18

The disadvantage of using an interquartile range is that

Accepted Answer

A)  it discards too much of the data. 
B)  it removes outliers only extremely high in value. 
C)  the positive and negative deviations balance out. 
D)  it is disproportionately influenced by outliers. 
A)  it discards too much of the data. 
B)  it removes outliers only extremely high in value. 
C)  the positive and negative deviations balance out. 
D)  it is disproportionately influenced by outliers.

Question 19

The whiskers in a boxplot

Accepted Answer

A)  always enclose all of the data points. 
B)  always run from the smaller inner fence to the larger inner fence. 
C)  encompass the H-spread only. 
D)  contain all data points outside the box except the outliers. 
A)  always enclose all of the data points. 
B)  always run from the smaller inner fence to the larger inner fence. 
C)  encompass the H-spread only. 
D)  contain all data points outside the box except the outliers.

Question 20

The US Census Bureau collected data on family composition and found that samples from different parts of the country gave very different results for the mean number of family members living in households. If all of the data were combined to one data set,

Accepted Answer

A)  the standard deviation of number of family members would probably be very small. 
B)  the standard deviation of number of family members would probably be relatively high. 
C)  the interquartile range would be small. 
D)  the median would equal the mean. 
A)  the standard deviation of number of family members would probably be very small. 
B)  the standard deviation of number of family members would probably be relatively high. 
C)  the interquartile range would be small. 
D)  the median would equal the mean.

Exam 5: Measures of Variability

In a boxplot the width of the box encompasses

The median is a measure of variability.

If we eliminate the top and bottom 25% of the data and take the range of what remains we have the

Answer the following questions based on this distribution of exam scores. a. What is the median? b. Are there outliers? c. Does the distribution seem skewed? If so, is it positively, or negatively skewed?

A "hinge" is another word for

The sample variance is a biased statistic.

Data points at the extremes of the distribution have

Of all of the measures of variability, the standard deviation is most susceptible to distortion due to outliers.

The vertical line in the center of a box plot

We normally compute the variance using N - 1 in the denominator because

Construct two small sets of data that have the same mean, but a different standard deviation.

The range is

The population variance is

If I continue to draw observations from a population and recalculate the mean each time I add an observation, the mean will approach _______ as the sample size increases.

The difference between the lowest to the highest score in a distribution is the range.

The equation is used to calculate the

We generally like the standard deviation when we are trying to describe a sample of data because

The disadvantage of using an interquartile range is that

The whiskers in a boxplot

The US Census Bureau collected data on family composition and found that samples from different parts of the country gave very different results for the mean number of family members living in households. If all of the data were combined to one data set,

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