I want to know whether drivers who drive with their headlights on ...

[Haya94]

I want to know whether drivers who drive with their headlights on in the daytime are less likely to have accidents. I require 100 drivers from a large company to drive with their lights on during the day and require another group of 100 drivers from the same company to keep their lights off. I then keep accident statistics for several years to see if there are any differences. Having the lights on or off in the daytime is
 
  A) the dependent variable.
  B) a confounding variable.
  C) a random variable.
  D) the independent variable.

Question 2

I am interested in whether students from University A or from University B are bigger sports fans. I make up a questionnaire asking questions such as What percentage of football games do you watch? and give it to a group of 100 women from University A and 100 men from University B. Suppose I find that the first group scores statistically lower on the test than the second group. If I conclude that University B students are bigger sports fans than University A students, I might be wrong because
 
  A) more of the University B students may have been juniors and seniors.
  B) the dependent variable was not well defined.
  C) there was no difference in the levels of the independent variable.
  D) there is a confounding variable.

[nmyers]

Answer to Question 1

D

Answer to Question 2

D

[Haya94]

Thank you

[nmyers]

No problem