Please answer all

Question 13 (0.4167 points)

Suppose we have quantitative variables X and Y, as well as a categorical variable named Group.

When do we use log(Group) in a model?

	When we want an interpretation using percentage differences when comparing the groups.
	When we want an interpretation using addition/subtraction differences when comparing the groups.
	Both of the above.
	None of the above.

Question 16 (0.4167 points)

Suppose we have a data set with quantitative variables X and Y, as well as a categorical variable Group (Group A, Group B, and Group C).

We use the R command

lm(log(Y) ~ X + Group), and are given the coefficients table below.

Variable	Estimate of coefficient
(intercept)	2
X	0.6
Group B	0.5
Group C	-0.3

After controlling for X, the predicted value of Y in Group B is ______ % higher than in Group A.

Answer

Question 19 (0.4167 points)

Suppose we have a data set named Data.

This data set contains variables Segment, Budget, and Profit.

We would like to complete the interpretation below. Which R command would we use?

Interpretation: After controlling for Segment, whenever the budget increases $100, the predicted profit increases _________ %.

	lm( log(Profit) ~ Budget + log(Segment), data=Data)
	lm( Profit ~ log(Budget) + log(Segment), data=Data)
	lm( log(Profit) ~ Budget + Segment, data=Data)
	lm( Profit ~ log(Budget) + Segment, data=Data)

Question 21 (0.4167 points)

The graph below shows the relationship between advertising budget, units sold, and team.

On the image below,

the values labeling the x-axis, advertising budget, are 1, 10, 100, 1000, 10000, and 100000

the values labeling the y-axis, units sold, are 10, 100, 1000, 10000, 100000, etc.

The dots are color coded by team, and trend lines that look like straight lines are included for each of the three teams. The three trend lines appear to be nearly equal to each other.

What type of trend lines are the three lines shown on the plot?

	There is an exponential trend line drawn for each of the three teams.
	There is a power law trend line drawn for each of the three teams.
	There is a logarithmic trend line drawn for each of the three teams.
	There is a linear trend line drawn for each of the three teams.