Question 1

10pts

You construct a scatterplot between two numerical variables and you observe that the points lie very close to a straight line, which rises as you look to the right. Which value of the correlation condition is most likely to be associated with this graph?

Group of answer choices

-.2

-.9

+.9

+.2

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Question 2

10pts

Make sure you have the CDC dataset loaded then run the following command.

boxplot(cdc$weight~cdc$gender)

IdentifyAllof the true statements below.

Group of answer choices

Men tend to be heavier than women

The Median weight for women is less than the 25th percentile of the weights of men.

The heaviest woman is about as heavy as the heaviest man.

There are more low weight male outliers than low weight female outliers.

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Question 3

10pts

Suppose that you are investigating a potential causal relationship where both the explanatory and response variable are numerical.What type of plot would you create?

Group of answer choices

A histogram

A side-by-side boxplot

A scatterplot

A mosaic plot

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Question 4

10pts

Suppose that you are investigating a potential causal relationship where the explanatory variable is categorical and the response variable is numerical.What type of plot would you create?

Group of answer choices

A histogram

A side-by-side boxplot

A scatterplot

A mosaic plot

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Question 5

10pts

You are investigating whether people who believe in biological evolution are more likely to want to require universal background checks for firearms purchases.You have a survey of 1,000 randomly selected students at the University of Michigan which had questions on these topics.What type of inferential problem is this?

Group of answer choices

A categorical explanatory variable and a categorical response.

A categorical explanatory variable and a numerical response

A numerical explanatory variable and a categorical response.

A numerical explanatory variable and a numerical response.

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Question 6

10pts

A friend of yours says that if he can see a persons belt size, he can predict the person's weight.You want to test her ability with data.What kind of inference problem is this?

Group of answer choices

A categorical explanatory variable and a categorical response.

A categorical explanatory variable and a numerical response

A numerical explanatory variable and a categorical response.

A numerical explanatory variable and a numerical response.

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Question 7

10pts

A friend of yours says that if she can see a persons shirt collar size, she can predict whether or not the person meets the definition of obesity.You want to test her ability with data.What kind of inference problem is this?

Group of answer choices

A categorical explanatory variable and a categorical response.

A categorical explanatory variable and a numerical response

A numerical explanatory variable and a categorical response.

A numerical explanatory variable and a numerical response.

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Question 8

10pts

Run the following three commands in order

x <- rnorm(100)

y <- 2*x + 3 + rnorm(100,sd=1)

z <- 2*x + 3 + rnorm(100,sd=2)

Calculate the correlation coefficients between x and y and between x and z.

Identify all of the true statements below?

Group of answer choices

Both coefficients are positive

The correlation between x and z is stronger than that between x and. y

The correlation between x and y is stronger than that between x and z

The correlation coefficients both indicate a lack of correlation between the two variables.

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Question 9

10pts

Compute the value of the correlation coefficient between height and weight in the CDC dataset. What value do you get?

Group of answer choices

.555

-.555

.515

-.515

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Question 10

10pts

Which of the following 4 R commands would produce the correlation coefficient between the numeric vectors x and y?

Group of answer choices

Corr(x,y)

cc(x,y)

cor(x,y)

r(x,y)