A study made by a psychologist shows that spending too much time in fr

Hello, havehope. To answer your first question, I would recommend you check out GMAT Ninja's CR Guide for Beginners if you have not already. The passage or question type is not nearly as important as developing a reliable method to break down whatever the test throws in front of you.

A major problem with this particular response is that some adults within one group are compared to others in the same group, rather than to those in the other group. The conclusion is based on comparing the experimental results from the two different groups, which we can call the three-hour group and the six-hour group. Comparing sixes to other sixes does nothing to advance or challenge the conclusion. It is not as though every member of a group must exhibit the same sleeping behavior. You should also, in general, be wary of the qualifying word some, which can mean just two. The word often appears in otherwise reasonable answers as a way of sidetracking the test-taker.

The second group is the six-hour group. If these people suffered beforehand from the very problems that the experiment was designed to study, then the arrow of causality is unclear. That is, perhaps the sixes were predisposed to, say, insomnia, and the fact that they worked on a computer for 6 hours a day or more had little or nothing to do with the research findings. This is one type of weakener, not the only one that could work here, but it is the best option of the five presented.

Perhaps the question makes more sense now. Good luck with your studies.

- Andrew