Name:    Correlation and Causation

Multiple Choice
Identify the choice that is the most likely explanation of the high correlation value.

1.

A higher number of ice cream sales corresponds to a higher number of shark attacks on swimmers.

 a. Causation (cause and effect) b. Common cause (related to a third variable) c. Coincidence

2.

The number of cavities in elementary school children and vocabulary size have a strong positive correlation. Does this mean that increasing the number of cavities in elementary school children CAUSES  their vocabulary size to increase? What explains this relationship?

 a. Causation b. Common cause c. Coincidence

3.

In a growing municipality, the traffic planner (who never completed Data Management class) observed that over a period of ten years the number of traffic accidents showed a high positive correlation with the number of traffic lights installed. Was the planner correct in suggesting to the Mayor that they remove all the traffic lights to reduce the accident rate? What is the relationship between these two variables?

 a. Causation b. Common cause c. Coincidence

4.

There is a strong, positive correlation between the number of fire engines responding to a fire and the size of the fire.  Does this suggest that reducing the number of responding fire engines will result in less fire damage?  Why or why not? What is the cause of the relationship between these variables?

 a. Causation b. Common cause c. Coincidence

5.

Every time that I eat chocolate, I get acne.  Does this mean that, for me, eating chocolate causes acne?  Why or why not? What is the connection between the two variables?

 a. Causation b. Common cause c. Coincidence

6.

It has been observed that the number of rings in a tree stump correspond roughly with the age of the tree.

 a. Causation b. Common cause c. Coincidence

7.

Humans have 23 chromosome pairs.  The earth’s axis is tilted at approximately 23 degrees.

 a. Causation b. Common cause c. Coincidence

8.

Discuss the observation that “Drivers of red cars are twice as likely to be involved in an accident as drivers of blue cars.”  Does this imply that driving a red car “causes” drivers to have an accident? What is the relationship here?

 a. Causation b. Common cause c. Coincidence

9.

Which of the following would you expect to have a negative correlation coefficent?
 a. Hours of study, examination score b. Speed in excess of the speed limit, amount charged on a traffic fine c. Hours of television watched per week, final mark in calculus d. A person’s height, sum of the digits in the person’s telephone number e. A person’s height, the person’s strength

10.

Which of the following is the dependent variable?
 a. Heart disease b. Cholesterol level c. Could be either

11.

Which of the following is the dependent variable?
 a. Hours of basketball practice b. Free-throw success rate c. Could be either

12.

Which of the following is the dependent variable?
 a. Amount of fertilizer used b. Height of plant c. Could be either

13.

Which of the following is the dependent variable?
 a. Income b. Level of education c. Could be either

14.

Which of the following is the dependent variable?
 a. Running speed b. Pulse rate c. Could be either