Chapter 7, Problem 4E

(a)

To determine

To find out which variable you want to use as the explanatory and response variable and why and what would you expect to see in the scatterplot and also discuss the likely direction, form and strength for the same.

Answer to Problem 4E

Time is the explanatory variable and the cost is the response variable.

There is a positive, completely linear relationship. The relationship is extremely strong.

Explanation of Solution

Now, we have to find out for the: Long distance calls; time in minutes and cost.

We know that, the response variable is the focus of a question in a study or experiment. An explanatory variable is one that explains changes in that variable. It can be anything that might affect the response variable.

As we can see that, time is the explanatory variable and the cost is the response variable because time is used to predict the cost of the call.

The relationship is positive because as time increases, cost increases as well. The relationship is completely linear because as time increases by one minute, the cost is expected to increase by the same amount every minute. The relationship is extremely strong because the relationship is completely linear.

(b)

To determine

To find out which variable you want to use as the explanatory and response variable and why and what would you expect to see in the scatterplot and also discuss the likely direction, form and strength for the same

Answer to Problem 4E

Distance is the explanatory variable and time delay is the response variable.

There is a positive, linear relationship. The relationship is strong.

Explanation of Solution

Now, we have to find out for the: Lightning strikes; distance from lightning and time delay of the thunder.

We know that, the response variable is the focus of a question in a study or experiment. An explanatory variable is one that explains changes in that variable. It can be anything that might affect the response variable.

As we can see that,distance is the explanatory variable and time delay is the response variable because distance is used to predict the time delay of thunder.

The relationship is positive because as distance from lightning increases, the time delays of thunder increases. The relationship is linear because as distance increases by one unit, the time delay will increase by approximately the same amount each time. The relationship is strong because of the strong linear relationship.

(c)

To determine

To find out which variable you want to use as the explanatory and response variable and why and what would you expect to see in the scatterplot and also discuss the likely direction, form and strength for the same

Answer to Problem 4E

Brightness is the explanatory variable and distance is the response variable.

There is a negative, linear relationship. The relationship is strong.

Explanation of Solution

Now, we have to find out for the: A streetlight; its apparent brightness and your distance from it.

We know that, the response variable is the focus of a question in a study or experiment. An explanatory variable is one that explains changes in that variable. It can be anything that might affect the response variable.

As we can see that,brightness is the explanatory variable and the distance is the response variable because brightness predicts your distance from the light.

The relationship is negative because as brightness increases, distance decreases. The relationship is linear because as brightness increases by the same amount, distance decreases by the same amount. The relationship is strong because of this linear relationship.

(d)

To determine

To find out which variable you want to use as the explanatory and response variable and why and what would you expect to see in the scatterplot and also discuss the likely direction, form and strength for the same

Answer to Problem 4E

Weight of car is the explanatory variable and age of owner is the response variable.

There is no relationship between the two variables.

Explanation of Solution

Now, we have to find out for the: Car; weight of the car and age of owner.

We know that, the response variable is the focus of a question in a study or experiment. An explanatory variable is one that explains changes in that variable. It can be anything that might affect the response variable.

As we can see that,weight of car is the explanatory variable and age of owner is the response variable because weight is used to predict the age of the owner.

There is no relationship because there is no correlation between the two variables.