In a recent study, each member of two groups of people Group A (compos

Question

In a recent study, each member of two groups of people, Group A (composed of persons sixty-five to seventy-five years old) and Group B (composed of college students), was required to make a telephone call to a certain number at a specified time. The time when each call was initiated was recorded electronically. Group A proved far better at remembering to make a telephone call precisely at a specified time than did Group B. There were fourteen lapses in Group B but only one lapse in Group A. Clearly, at least one type of memory does not suffer as a person ages.

Which one of the following, if all of them are true, is LEAST helpful in establishing that the conclusion above is properly drawn?

(A) There was the same number of people in each group.

(B) The same group of researchers answered the calls made by the callers in both study groups.

(C) Among the college students there were no persons more than forty years old.

(D) Both groups had unrestricted access to telephones for making the required calls.

(E) The members of the two groups received their instructions approximately the same amount of time before they were to make their telephone calls.

Show Spoiler

Attachment:

LSAT CR 42 9.PNG [ 78.34 KiB | Viewed 10082 times ]

Show Answer

Official Answer

Official Answer and Stats are available only to registered users. Register/Login.

GMATNinja · Accepted Answer

The author's conclusion is that "at least one type of memory {i.e. the type required to remember to make a phone call at a certain time} does not suffer as a person ages. How does the author arrive at that conclusion?

A recent study compared Group A (persons sixty-five to seventy-five years old) to Group B (college students). 
 Each member of the two groups was asked to call a certain phone number at a certain time. 
 "The time when each call was initiated was recorded electronically", allowing the scientists conducting the study to see whether the group members made the calls at the requested times. 
 "Group A proved far better at remembering to make a telephone call precisely at a specified time than did Group B." In other words, members of Group A did a better job of making the phone calls at the specific times requested. 
 How much better did Group A do compared to Group B? "There were 14 lapses in Group B but only one lapse in Group A."

Thus, it seems as though the members of Group A were better able to remember to make a phone call at a certain time. But what information would be useful in establishing whether that line of reasoning is accurate? Any statement that IS useful should be eliminated because we are looking for the statement that would be the LEAST useful:

Yes, this would be useful to know. What if Group B had 1000 members but Group A only had 10? In that case, the difference in the number of lapses could be contributed to group size, not to a difference in memory between the two groups. Thus, (A) should be eliminated.

All we need to know is whether the group members made their calls at the specific requested times. "The time when each call was initiated was recorded electronically," so it doesn't matter who answered the calls. (B) does NOT help us evaluate the argument or conclusion, so let's hang on to it.

Remember, the conclusion is that "at least one type of memory does not suffer as a person ages." This conclusion is based on evidence comparing a group of college students to a group of persons sixty-five to seventy-five years old. This argument ASSUMES that the college students were much younger, but what if that was not the case? What if most of the college students participating in the study were actually older adults or even senior citizens over sixty-five years old? That would certainly harm the author's argument. Statement (C) WOULD be useful in evaluating the conclusion, so it should be eliminated.

What if the college students (Group B) did not have unrestricted access to telephones while the members of Group A did have such access? In that case, the difference in the number of lapses could be contributed to telephone access, not to a difference in memory between the two groups. Thus, (D) would be helpful and should be eliminated.

Again, this would provide an alternate reason to explain the difference in the number of lapses. If the college students in Group B were only give a very short amount of time and the members of Group A were given a lot of time, that might have given the members of Group A more time to prepare and make sure they would be ready to make the calls at the specified times. (E) would be helpful and should be eliminated.

Choice (B) is the best answer.

I hope that helps clear up some of the confusion!

RaguramanS · Answer

OE:

Premise:
As a person ages, his/her memory deteriorates. This is proved by evidencing the lapses in both groups. One memory doesn't have an effect on age.

Keyword:
The question stem is a little tricky. It is a strengthen question. So hunt for the additional information that can bolster the conclusion

POE
A.The correlation is between age and memory not numbers  Wrong 
B. This option intends to address the legitimacy of the research. This must be true. If different people answer the calls, then there might be other reason for the lapses. For example, the person attending the call might intentionally delay in answering the query.  Correct 
C. This is mere an inference.  Wrong 
D. This information does not address the correlation between the age and memory  Wrong 
E. This addresses that there is no delay in the starting time of the event. Irrelevant  Wrong

yell2012 · Answer

Could somebody explain...

Dear Experts, especcially GMATNinja I need your help I did not understand why correct answer is B

prithvishuppal · Answer

This is a strengthen "except" question so 4 of the answer choices will strengthen the argument whereas one answer choice will have no impact.

The arguments conclusion in that as a person ages, he/she does not suffer from at least one kind of memory loss.

If you pre-think about potential loopholes in this argument (strengthening is about closing loopholes), we could possible think of difference in the group numbers - what if the old people group had only 5 members are 1 failed to call, whereas the young group had 100 members and 14 forgot, then clearly group of the younger folks is better (20% vs 14%) and the conclusion fails. Alternatively, what if the younger group was just busy and had other things to do and just couldnt call despite remembering. or that the young peoples group were told 1 hour ago and the old people were told just 1 min before to place their call. Closing these loopholes would strengthen the argument.

A. Strengthens - as explained above. It closes 1 loophole
B. we arent really concerned with who answered the calls. we care about who made the calls - so this option has no impact on the argument. keep as contender
C. Slightly strengthens - even if confused, B looks a better bet. this may strengthen if we assume that the older people of the young group forgot to make calls. this option closes that loophole.
D. Strengthens - what if the young group were from an impoverished background and could afford a telephone (i.e had no access). so the study would not be conclusive. maybe those 14 people all would have placed a call and only that 1 old man/woman would not have done so. this option closes that loophole.
E. strengthens - again this options says that there was an even playing field b/w the 2 groups.

thus option B has no impact on the argument and plays no role in strengthening it!

Yellkrishna · Answer

A. This helps since it establishes parity between the groups. 
B. The question is whether B has good skills of remembering some things or not. Who answers the call is irrelevant. Good. 
C. This helps to establish that there is no overlap b/w the groups. 
D. Same as A. 
E. Same as A.
 Hence B.

Posted from my mobile device

VerbalBot · Answer

Automated notice from GMAT Club VerbalBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.

In a recent study, each member of two groups of people Group A (compos

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

GMAT Critical Reasoning (CR) Questions

In a recent study, each member of two groups of people Group A (compos

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia