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Return to Research Methods Using R 1e Student Resources
Chapter 3 Multiple choice questions
Quiz Content
*
not completed
.
Download the data file for the multiple-choice questions for Chapter 3
, and open it in
R
. Inspect the data objects
a
and
b
. Which of the following best describes them?
Both objects are in wide format
correct
incorrect
Both objects are in long format
correct
incorrect
Object
a
is in wide format, and
b
is in long format
correct
incorrect
Object
b
is in wide format, and
a
is in long format
correct
incorrect
*
not completed
.
Plot a histogram of the Measure column of b. How do the data appear?
Approximately normally distributed
correct
incorrect
Positively skewed
correct
incorrect
Negatively skewed
correct
incorrect
Uniformly distributed
correct
incorrect
*
not completed
.
Use the
boxplot
function to display the data stored in
outlierdata
. How would you describe the results?
There is a single outlier above the inner fence
correct
incorrect
There is a single outlier below the inner fence
correct
incorrect
There are multiple outliers on either side of the inner fence
correct
incorrect
There are no outliers
correct
incorrect
*
not completed
.
What is the standard deviation of
outlierdata
?
-0.04
correct
incorrect
0.12
correct
incorrect
1.15
correct
incorrect
1.22
correct
incorrect
*
not completed
.
Calculate Chauvenet's criterion using the function on page 28. Use it to identify the index and value of any outliers in
outlierdata
.
There are no outliers according to this measure
correct
incorrect
There is one outlier in row 72, with a value of -2.48
correct
incorrect
There are two outliers in rows 72 and 37, with values of -2.48 and 7.1
correct
incorrect
There is one outlier in row 37, with a value of 7.1
correct
incorrect
*
not completed
.
The two columns of
mvdata
contain two different dependent variables. Use the
mahalanobis
function to calculate the squared Mahalanobis distance for each pair of points. The largest value is:
26.02
correct
incorrect
9.72
correct
incorrect
2.34
correct
incorrect
3.12
correct
incorrect
*
not completed
.
Use the
scale
function to rescale the data in
mvdata$DV2
by its standard deviation, but do not subtract the mean. The new mean after rescaling is:
0.99
correct
incorrect
-3.86*10
^{-16}
correct
incorrect
-1.12*10
^{-15}
correct
incorrect
20.04
correct
incorrect
*
not completed
.
Conduct a Kolmogorov-Smirnov test on the data in
b$Measure
. What is the outcome?
The test is not significant (
p
>0.05), indicating the data are not normally distributed
correct
incorrect
The test is not significant (
p
>0.05), indicating the data are normally distributed
correct
incorrect
The test is significant (
p
<0.05), indicating the data are not normally distributed
correct
incorrect
The test is significant (
p
<0.05), indicating the data are normally distributed
correct
incorrect
*
not completed
.
Calculate a square root transform of the data in b$Measure using the
sqrt
function, and repeat the Kolmogorov-Smirnov test on the transformed data. What is the outcome?
The test is not significant (
p
>0.05), indicating the data are not normally distributed
correct
incorrect
The test is not significant (
p
>0.05), indicating the data are normally distributed
correct
incorrect
The test is significant (
p
<0.05), indicating the data are not normally distributed
correct
incorrect
The test is significant (
p
<0.05), indicating the data are normally distributed
correct
incorrect
*
not completed
.
Use the qqnorm and qqline functions to create a Q-Q plot of b$Measure. Which description is most accurate?
The points fall close to the line
correct
incorrect
Most points at the extremes are below the line
correct
incorrect
Most points at the extremes are above the line
correct
incorrect
Points at the extremes are both above and below the line
correct
incorrect
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