GMATPrep CR

The author's conclusion is the following:

It had been assumed that people lack sufficient free time to maintain current television-viewing levels while spending increasing amounts of free time on the computer. The author conclusion is that this is false because time spent using the computer has increased and time spent watching TV hasn't changed. So the author conclusion is that people have enough time to use the computer and watch TV

Now you have to apply the variance test among the answer choices, looking for different effects in the conclusion. You have to look for an answer choice that if true weakens/strengthens the argument and if false strengthens/weakens the argument.

A. Whether a large majority of the survey respondents reported watching television regularly

Whether this is true/false does not matter since we are interested in the amount of time spent, but not in how often people watch TV.

B. Whether the amount of time spent watching television is declining among people who report that they rarely or never use computers

The conclusion covers people who use computers and people who do not. So if you reduce the scope to people who rarely or never use computers, you can't use the information to evaluate the argument.

C. Whether the type of television programs a person watches tends to change as the amount of time spent per week using computers increases

Again you have to keep the scope of the argument, amount of time spent on watching television vs amount of time spent on using computers. You are not interested in whether the types of television programs changes.

D. Whether a large majority of the computer owners in the survey reported spending increasing amounts of time per week using computers

Notice the shift in the scope since this question only talks about computer owners and the conclusion includes all the respondents. You can't use this information to evaluate the argument.

E. Whether the survey respondents’ reports of time spent using computers included time spent using computers at work

if this is true, it weakens the author's conclusion because the increased in time spent using computers includes time at work, so perhaps people do not have enough free time to watch TV and use the computer.

If this is false, it strengthens the author's conclusion because people have used computers outside work (free time) and the time spent watching TV hasn't changed. Therefore people must have enough free time to use computers and to watch TV.