Question 1

Which of the following is not a goal of re-expressing data?

Accepted Answer

A) Make the scatter in a scatterplot spread out evenly rather than following a fan shape. 
B) Make the spread of several groups more alike. 
C) All of these are goals of re-expressing data. 
D) Make the form of a scatterplot more nearly linear. 
E) Make the distribution of a variable more symmetric. 
A) Make the scatter in a scatterplot spread out evenly rather than following a fan shape. 
B) Make the spread of several groups more alike. 
C) All of these are goals of re-expressing data. 
D) Make the form of a scatterplot more nearly linear. 
E) Make the distribution of a variable more symmetric. C

Question 2

In predicting the growth of the volume of a small bay by measuring the height of the water at a dock, a researcher is using a model of $\sqrt [ 3 ] { \widehat { volume} } = 2.34 + 4.56$ (height) where height is measured in $\mathrm { m }$ and volume cubic miles. If the height rises to $3.45 \mathrm {~m}$, what is the predicted volume?

Accepted Answer

A)  $2.62 \mathrm {~m} ^ { 3 }$ 
B)  $1.2 \times 10 ^ { 12 } \mathrm {~m} ^ { 3 }$ 
C)  $5902 \mathrm {~m} ^ { 3 }$ 
D)  $7 \times 10 ^ { 7 } \mathrm {~m} ^ { 3 }$ 
E)  $18.1 \mathrm {~m} ^ { 3 }$ 
A)  $2.62 \mathrm {~m} ^ { 3 }$ 
B)  $1.2 \times 10 ^ { 12 } \mathrm {~m} ^ { 3 }$ 
C)  $5902 \mathrm {~m} ^ { 3 }$ 
D)  $7 \times 10 ^ { 7 } \mathrm {~m} ^ { 3 }$ 
E)  $18.1 \mathrm {~m} ^ { 3 }$ C

Question 3

Over the past decade a farmer has been able to increase his wheat production by about the Same number of bushels each year.His most useful predictive model is probably…

Accepted Answer

A) linear 
B) logarithmic 
C) quadratic 
D) exponential 
E) power 
A) linear 
B) logarithmic 
C) quadratic 
D) exponential 
E) power A

Question 4

A residual plot that has no pattern is a sign that…

Accepted Answer

A) the original data is straight and the regression line is a good model. 
B) the original data is straight and the regression line is not a good model. 
C) the model is not a good one, because there is no pattern. 
D) the original data is curved and the regression line is not a good model. 
A) the original data is straight and the regression line is a good model. 
B) the original data is straight and the regression line is not a good model. 
C) the model is not a good one, because there is no pattern. 
D) the original data is curved and the regression line is not a good model.

Question 5

Which statement about re-expressing data is not true?
I.Unimodal distributions that are skewed to the left will be made more symmetric by taking The square root of the variable.
II.A curve in which the direction of the association changes from negative to positive will Not benefit from re-expression.
III.One goal of re-expression may be to make the variability of the response variable more Uniform.

Accepted Answer

A) I only 
B) III only 
C) II only 
D) II and III 
E) I,IIandIII 
A) I only 
B) III only 
C) II only 
D) II and III 
E) I,IIandIII

Question 6

When using midterm exam scores to predict a student's final grade in a class, the student Would prefer to have a

Accepted Answer

A) negative residual, because that means the student's final grade is lower than we would predict with the model. 
B) residual equal to zero, because that means the student's final grade is exactly what we would predict with the model. 
C) positive residual, because that means the student's final grade is lower than we would predict with the model. 
D) positive residual, because that means the student's final grade is higher than we would predict with the model. 
E) negative residual, because that means the students final grade is higher than we would predict with the model. 
A) negative residual, because that means the student's final grade is lower than we would predict with the model. 
B) residual equal to zero, because that means the student's final grade is exactly what we would predict with the model. 
C) positive residual, because that means the student's final grade is lower than we would predict with the model. 
D) positive residual, because that means the student's final grade is higher than we would predict with the model. 
E) negative residual, because that means the students final grade is higher than we would predict with the model.

Question 7

The model$\sqrt{\widehat{\text { distance }}}$  = 3.30 + 0.235 (speed. can be used to predict the stopping distance (in feet. for a car traveling at a specific speed (in mph.) According to this model, about how much distance will a car going $65 \mathrm { mph }$ need to stop?

Accepted Answer

A)  $729.0$ feet 
B)  $345.0$ feet 
C)  $27.0$ feet 
D)  $4.3$ feet 
E)  $18.6$ feet 
A)  $729.0$ feet 
B)  $345.0$ feet 
C)  $27.0$ feet 
D)  $4.3$ feet 
E)  $18.6$ feet

Question 8

Which is true?
I.Random scatter in the residuals indicates a model with high predictive power.
II.If two variables are very strongly associated, then the correlation between them will be near +1.0 or -1.0.
III.The higher the correlation between two variables the more likely the association is based in cause and effect.

Accepted Answer

A) I, II, and III 
B) none 
C) I only 
D) I and II 
E) II only 
A) I, II, and III 
B) none 
C) I only 
D) I and II 
E) II only

Question 9

Two variables that are actually not related to each other may nonetheless have a very high Correlation because they both result from some other, possibly hidden, factor.This is an Example of

Accepted Answer

A) leverage. 
B) regression. 
C) an outlier. 
D) a lurking variable. 
E) extrapolation. 
A) leverage. 
B) regression. 
C) an outlier. 
D) a lurking variable. 
E) extrapolation.

Question 10

A residuals plot is useful because
I.it will help us to see whether our model is appropriate.
II.it might show a pattern in the data that was hard to see in the original scatterplot.
III.it will clearly identify influential points.

Accepted Answer

A) I and II only 
B) I, II, and III 
C) II only 
D) I only 
E) I and III only 
A) I and II only 
B) I, II, and III 
C) II only 
D) I only 
E) I and III only

Question 11

Another farmer has increased his wheat production by about the same percentage each year.
His most useful predictive model is probably…

Accepted Answer

A) linear 
B) exponential 
C) logarithmic 
D) quadratic 
E) power 
A) linear 
B) exponential 
C) logarithmic 
D) quadratic 
E) power

Question 12

The $\sqrt { \widehat { s t r } } = 12 + 20 ($ dia $)$ can be used to predict the breaking strength of a rope (in pounds) from its diameter (in inches). According to this model, how much force should a rope onehalf inch in diameter be able to withstand?

Accepted Answer

A)  $16 \mathrm { lbs }$ 
B)  $22 \mathrm { lbs }$ 
C)  $4.7 \mathrm { lbs }$ 
D)  $256 \mathrm { lbs }$ 
E)  $484 \mathrm { lbs }$ 
A)  $16 \mathrm { lbs }$ 
B)  $22 \mathrm { lbs }$ 
C)  $4.7 \mathrm { lbs }$ 
D)  $256 \mathrm { lbs }$ 
E)  $484 \mathrm { lbs }$

Question 13

Which statement about correlation is true?
I.Regression based on data that are summary statistics tends to result in a higher
Correlation.
II. $\text { If } r = 0.95 , \text { the response variable increases as the explanatory variable increases. }$
III.An outlier always decreases the correlation.

Accepted Answer

A) I only 
B) II only 
C) III only 
D) I, II, and III 
E) none of these 
A) I only 
B) II only 
C) III only 
D) I, II, and III 
E) none of these

Question 14

If a data point is influential it…

Accepted Answer

A) has a small residual. 
B) is guaranteed to be extreme in the vertical direction. 
C) is guaranteed to be extreme in the horizontal direction. 
D) will change the slope of the regression equation. 
E) none of these. 
A) has a small residual. 
B) is guaranteed to be extreme in the vertical direction. 
C) is guaranteed to be extreme in the horizontal direction. 
D) will change the slope of the regression equation. 
E) none of these.

Question 15

Which of the following is not a source of caution in regression between two variables?

Accepted Answer

A) subgroups with differences 
B) extrapolation 
C) a lurking variable 
D) an outlier 
E) all of these are potential problems. 
A) subgroups with differences 
B) extrapolation 
C) a lurking variable 
D) an outlier 
E) all of these are potential problems.

Question 16

Which statement about residuals plots is true?
I.A curved pattern indicates nonlinear association between the variables.
II.A pattern of increasing spread indicates the predicted values become less reliable as the
Explanatory variable increases.
III.Randomness in the residuals indicates the model will predict accurately.

Accepted Answer

A) I only 
B) II only 
C) I, II, and III 
D) I and III only 
E) I and II only 
A) I only 
B) II only 
C) I, II, and III 
D) I and III only 
E) I and II only

Question 17

Linear regression was used to describe the trend in world population over timE.Below is a
Plot of the residuals versus predicted values.What does the plot of residuals suggest?

Accepted Answer

A) An outlier is present in the data set. 
B) The linearity condition is not satisfied. 
C) A high leverage point is present in the data set. 
D) The data are not normal. 
A) An outlier is present in the data set. 
B) The linearity condition is not satisfied. 
C) A high leverage point is present in the data set. 
D) The data are not normal.

Question 18

A scatterplot of log(Y) vs.log(X) reveals a linear pattern with very little scatter.It is Probably true that …

Accepted Answer

A) the calculator's LnReg function will model the association between X and Y. 
B) the residuals plot for regression of Y on X shows a curved pattern. 
C) the correlation between X and Y is near 0. 
D) the correlation between X and Y is near +1. 
E) the scatterplot of Y vs X shows a linear association. 
A) the calculator's LnReg function will model the association between X and Y. 
B) the residuals plot for regression of Y on X shows a curved pattern. 
C) the correlation between X and Y is near 0. 
D) the correlation between X and Y is near +1. 
E) the scatterplot of Y vs X shows a linear association.

Which of the following is not a goal of re-expressing data?

Over the past decade a farmer has been able to increase his wheat production by about the Same number of bushels each year.His most useful predictive model is probably…

A residual plot that has no pattern is a sign that…

When using midterm exam scores to predict a student's final grade in a class, the student Would prefer to have a

The model $\sqrt{\widehat{\text { distance }}}$ = 3.30 + 0.235 (speed. can be used to predict the stopping distance (in feet. for a car traveling at a specific speed (in mph.) According to this model, about how much distance will a car going $65 \mathrm { mph }$ need to stop?

Two variables that are actually not related to each other may nonetheless have a very high Correlation because they both result from some other, possibly hidden, factor.This is an Example of

A residuals plot is useful because I.it will help us to see whether our model is appropriate. II.it might show a pattern in the data that was hard to see in the original scatterplot. III.it will clearly identify influential points.

Another farmer has increased his wheat production by about the same percentage each year. His most useful predictive model is probably…

The $\sqrt { \widehat { s t r } } = 12 + 20 ($ dia $)$ can be used to predict the breaking strength of a rope (in pounds) from its diameter (in inches). According to this model, how much force should a rope onehalf inch in diameter be able to withstand?

Which statement about correlation is true? I.Regression based on data that are summary statistics tends to result in a higher Correlation. II. $\text { If } r = 0.95 , \text { the response variable increases as the explanatory variable increases. }$ III.An outlier always decreases the correlation.

If a data point is influential it…

Which of the following is not a source of caution in regression between two variables?

Linear regression was used to describe the trend in world population over timE.Below is a Plot of the residuals versus predicted values.What does the plot of residuals suggest?

A scatterplot of log(Y) vs.log(X) reveals a linear pattern with very little scatter.It is Probably true that …

Stats Starts Here

Displaying and Describing Data

Relationships Between Categorical Variablescontingency Tables

Understanding and Comparing Distributions

The Standard Deviation As a Ruler and the Normal Model

Scatterplots, Association, and Correlation

Linear Regression

Multiple Regression

Sample Surveys

Experiments and Observational Studies

From Randomness to Probability

Sampling Distribution Models and Confidence Intervals for Proportions

Confidence Intervals for Means

Testing Hypotheses

More About Tests and Intervals

Comparing Groupspaired

Samples and Blocks

Comparing Counts

Filters

Exam 8: Regression Wisdom

Which of the following is not a goal of re-expressing data?

Over the past decade a farmer has been able to increase his wheat production by about the Same number of bushels each year.His most useful predictive model is probably…

A residual plot that has no pattern is a sign that…

When using midterm exam scores to predict a student's final grade in a class, the student Would prefer to have a

Two variables that are actually not related to each other may nonetheless have a very high Correlation because they both result from some other, possibly hidden, factor.This is an Example of

A residuals plot is useful because I.it will help us to see whether our model is appropriate. II.it might show a pattern in the data that was hard to see in the original scatterplot. III.it will clearly identify influential points.

Another farmer has increased his wheat production by about the same percentage each year. His most useful predictive model is probably…

The str^=12+20(\sqrt { \widehat { s t r } } = 12 + 20 (str​=12+20( dia ))) can be used to predict the breaking strength of a rope (in pounds) from its diameter (in inches). According to this model, how much force should a rope onehalf inch in diameter be able to withstand?

If a data point is influential it…

Which of the following is not a source of caution in regression between two variables?

Linear regression was used to describe the trend in world population over timE.Below is a Plot of the residuals versus predicted values.What does the plot of residuals suggest?

A scatterplot of log(Y) vs.log(X) reveals a linear pattern with very little scatter.It is Probably true that …

Stats Starts Here

Displaying and Describing Data

Relationships Between Categorical Variablescontingency Tables

Understanding and Comparing Distributions

The Standard Deviation As a Ruler and the Normal Model

Scatterplots, Association, and Correlation

Linear Regression

Multiple Regression

Sample Surveys

Experiments and Observational Studies

From Randomness to Probability

Sampling Distribution Models and Confidence Intervals for Proportions

Confidence Intervals for Means

Testing Hypotheses

More About Tests and Intervals

Comparing Groupspaired

Samples and Blocks

Comparing Counts

Filters

The $\sqrt { \widehat { s t r } } = 12 + 20 ($ dia $)$ can be used to predict the breaking strength of a rope (in pounds) from its diameter (in inches). According to this model, how much force should a rope onehalf inch in diameter be able to withstand?