A large-scale study of adults over fifty years old who spent an averag

Question

A large-scale study of adults over fifty years old who spent an average of four to eleven hours a day sitting found that the mortality rates of those who spent less time sitting were consistently lower over three years - even after controlling for age, weight, general health, and exercise frequency, all of which affect mortality rates. The researchers concluded that most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting.

We do one study and then we generalize that study for most adults over 50. The study focusses on the people who spend an average of 4 to 11 hours. But how about the people who spend less than 4 hrs or more then 11 hrs. They are not part of the study.

In order to assess the strength of the researchers' reasoning, it would be most helpful to know whether most adults over fifty years old

A) who spend less time sitting exercise more frequently - No. This has been accounted for already.

B) spend less than eleven hours a day sitting - They can benefit from this either way.

C) who are in poorer general health are therefore inclined to spend more time sitting - No. General health has been accounted for already.

D) spend at least four hours a day sitting - This is important because if most adults spend less than 4 hours say 1 hr. even no hr sitting, how can they reduce their mortality rate by sitting less when they are already sitting less.

E) who participated in the study were approximately consistent in the numbers of hour they spent sitting each day - consistency is out of scope. We need between average 4 to 11 hrs.

MartyMurray · Accepted Answer

Explanation

A large-scale study of adults over fifty years old who spent an average of four to eleven hours a day sitting found that the mortality rates of those who spent less time sitting were consistently lower over three years - even after controlling for age, weight, general health, and exercise frequency, all of which affect mortality rates. The researchers concluded that most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting.

The conclusion of the argument is the following:

most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting

The conclusion is supported by the following:

A large-scale study of adults over fifty years old who spent an average of four to eleven hours a day sitting found that the mortality rates of those who spent less time sitting were consistently lower over three years - even after controlling for age, weight, general health, and exercise frequency, all of which affect mortality rates.

We see that the researchers have observed a correlation between amount of time sitting and mortality rate and concluded, basically, that the first causes the second.

In order to assess the strength of the researchers' reasoning, it would be most helpful to know whether most adults over fifty years old

The correct answer will be the one such that, if most older adults over fifty years old do it, the argument is strengthened or weakened and, if most of them do not do it, the effect on the argument will be the opposite of the effect of the fact that they do it.

A) who spend less time sitting exercise more frequently

This choice is interesting.

If adults who spend less time sitting exercise more frequently, then maybe exercising rather than sitting less is the reason for the lower mortality rate of those who sit less. In that case, we could seem to have information that there is a possible alternative reason for the correlation between amount of sitting and mortality rate, which would weaken the argument.

On the other hand, if adults who spend less time sitting do not exercise more frequently, then we may have ruled out an alternative reason for the correlation between the amount of sitting people do and the mortality rate. In that case, we could seem to have ruled out that exercising more is the reason for the lower mortality rate of those who sit less and thus strengthened the argument.

So, it could seem that knowing whether adults over fifty years old who spend less time sitting exercise more frequently would be helpful in evaluating the argument, and thus this choice is exactly the kind of choice we'd expect to see in an Evaluate the Argument question involving a cause-effect type of conclusion.

However, we have to be careful not to just look for familiar patterns in Critical Reasoning.

Also, we have to pay close attention to details of the passage, and in this case, the passage says the following:

even after  controlling for  age, weight, general health, and  exercise frequency , all of which affect mortality rates

We see that the passage indicates that the researchers have already controlled for exercise frequency. In other words, they have ruled out exercise frequency as a factor involved in the correlation between amount of time spent sitting and mortality rate.

So, information on whether adults who spend less time sitting exercise more frequently has no effect on the case for the researchers' conclusion.

Eliminate.

B) spend less than eleven hours a day sitting

This choice makes no difference either way.

Regardless of whether most adults over fifty years old spend less than eleven hours a day sitting, the researchers have found that, for the ones who spend four to eleven hours a day sitting, the less they sit, the lower the mortality rate.

In other words, maybe most adults don't spend less than eleven hours sitting. Maybe most spend eleven hours sitting. In that case, the evidence provided is still a reason to believe the conclusion.

Eliminate.

C) who are in poorer general health are therefore inclined to spend more time sitting

This choice is interesting.

If adults who are in poorer general health are therefore inclined to spend more time sitting, then maybe the observed correlation between amount of time spent sitting and mortality rate doesn't mean there is a cause-effect relationship between sitting and mortality. It could instead be that poorer general health causes both sitting and mortality.

So, the fact that adults who are in poorer general health are therefore inclined to spend more time sitting could seem to weaken the case for the researcher's conclusion.

On the other hand, information that adults who are in poorer general health are not therefore inclined to spend more time sitting could seem to serve to rule out an alternative reason for the correlation between the amount of sitting people do and the mortality rate. So, that information could seem to strengthen the argument.

So, it could seem that knowing whether adults who are in poorer general health are therefore inclined to spend more time sitting would be helpful in evaluating the argument, and thus this choice is exactly the kind of choice we'd expect to see in an Evaluate the Argument question involving a cause-effect type of conclusion.

However, we have to be careful not to just look for familiar patterns in Critical Reasoning.

Also, we have to pay close attention to details of the passage, and in this case, the passage says the following:

even after  controlling for  age, weight,  general health , and exercise frequency, all of which affect mortality rates

We see that the passage indicates that the researchers have already controlled for general health. In other words, they have ruled out general health as a factor involved in the correlation between amount of time spent sitting and mortality rate.

So, information on whether adults over 50 who are in poorer general health are therefore inclined to spend more time sitting has no effect on the case for the researchers' conclusion.

Eliminate.

D) spend at least four hours a day sitting

The argument is based on information adults who spend four to eleven hours a day sititng, but if "most adults over fifty years old" spend less than four hours a day sitting then maybe what the researchers found doesn't apply to "most adults over fifty years old."

On other other hand, if most adults over 50 years old spend at least four hours a day sitting, then what the researchers' found does apply.

That said this choice is similar to (B), and we eliminated (B). So, why not eliminate this choice too?

Here's the thing.

We've shown for sure that (A), (C), and (E) cannot work. Thus, we're down to (B) and (D). So, we need to choose between those two, and there's a key difference between them.

(B) is "spend less than eleven hours a day sitting." Notice that, if they do not "spend less than eleven hours a day sitting," then they could still spend eleven hours a day sitting, which is within the range of the study.

On the other hand, (D) is spend at least four hours a day sitting. If they do not "spend at least four hours a day sitting" then they are already spending less time sitting than anyone involved in the study spent. So, they are not in the range studied. They are already beating it for sure.

So, since we have to choose one, we choose (D).

Keep.

E) who participated in the study were approximately consistent in the numbers of hour they spent sitting each day

The passage say that the adults studied "spent an average of four to eleven hours a day sitting." So, the conclusion is based on average amounts of time spent sitting, not on numbers of hours spent on each individual day.

Thus, regardless of whether the adults who participated in the study were approximately consistent in the numbers of hour they spent sitting each day, the study results still support the conclusion, since the conclusion is based on averages, which will be the same regardless of whether the study participants were approximately consistent in the numbers of hour they spent sitting each day.

Eliminate.

Correct anwer:  D

KarishmaB · Answer

It was a tough question. I had to go quite extreme to get the answer but then, that is what we are expected to do in "Useful to Evaluate'' questions. Premises: A large-scale study of adults over fifty years old who spent an average of 4-11 hours a day sitting found that the mortality rates of those who spent less time sitting were consistently lower over three years - even after controlling for age, weight, general health, and exercise frequency. Conclusion: Most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting. A study was conducted on 50+ year olds who spent an average of 4-11 hours a day sitting. Those who spent < 4 or > 11 were not included in the study. The results were adjusted for their age, weight, general health, and exercise frequency. So essentially, you can consider that these factors were equal for all of them. It was concluded that most people can lower their mortality risk just by spending less time sitting. Question stem: In order to assess the strength of the researchers' reasoning, it would be most helpful to know whether most adults over fifty years old... We need to find that which of the following information about "most adults over fifty years old" will be helpful in evaluating the claim. A) who spend less time sitting exercise more frequently We had adjusted for exercise. Ignore. B) spend less than eleven hours a day sitting The result shows that lower the hours of sitting, lower the mortality risk. Yes/No Test: YES: If most adults over 50 spend less than 11 hours, they can reduce their mortality risk by spending less time sitting. The study includes people between 4 to 11 hours. Hence most people are likely to be similar to the group that was studied. NO: If most adults over 50 spend more than 11 hours, they can reduce their mortality risk by spending less time sitting. C) who are in poorer general health are therefore inclined to spend more time sitting We had adjusted for general health. Ignore. D) spend at least four hours a day sitting Here is the thing - what if most adults over 50 do not sit at all? Can they reduce their mortality risk by spending less time sitting? No. When they have no sitting time, they cannot reduce it. Yes/No Test: YES, most adults over 50 do spend at least four hours a day sitting - Great! They can reduce this to reduce mortality risk. Researcher's claim works. Most people are similar to the ones who were studied. NO, most adults over 50 spend less than four hours a day sitting - They are already spending little to no time sitting. How can they further reduce it to reduce mortality risk? Researcher's claim doesn't work. Most people are not similar to the ones who were studied. We don't know whether the conclusion applies to them. Correct. E) who participated in the study were approximately consistent in the numbers of hour they spent sitting each day. Consistency over the days has no role to play. We are talking about average over 3 years. So overall active life vs sedentary life. Ignore. Answer (D) Discussion on Useful to Evaluate Questions: https://youtu.be/1JtHjH1lWZc

TOBEATHATPERSON · Answer

Passage conclusion is that 
"most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting"

C) who are in poorer general health are therefore inclined to spend more time sitting
This is irrelevant because we only interesting spending less time sitting

D) keyword is "most" 
we don't know most people could lower mortality risk because most people may not be in 4hours <= part.
So the answer is D

katkot · Answer

MartyMurray  I also choose C but the official answer is D. This is GMAT Prep (Focus) question.

I do no understand how.

MartyMurray · Answer

On wow. I"ve edited my explanation. I think you'll see what's going on now.

sayan640 · Answer

KarishmaB  Thank you for responding. But you dint reject the option B by using the YES/No Technique.
I am trying to apply YES/NO technique on option B.

The conclusion is :- Most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting.

OPTION B when YES,
Most adults spend less than eleven hours a day sitting , then answer is YES , They could lower their mortality risk over the next three years just by spending less time sitting , provided they fall in the range of 4-11 hours ' time  and dont spend very little time sitting .

OPTION B when NO ,
Most adults spend more than eleven hours a day sitting , then also the answer is YES , They could lower their mortality risk over the next three years just by spending less time sitting because they have the bandwidth which they can lower down.

Since on both these extremes , the answer is  YES  , we are rejecting option B.  KarishmaB  Am I correct ?  chetan2u

KarishmaB · Answer

It is correct. I have added the test discussion to (B) too.

Hoehenheim · Answer

This is a rather simple question when you think less of it. Evaluate type questions are tricky, and if you have done a good chunk of weaken-strengthen questions, you would land on that C button faster than a kamikaze. If your instinct was to go for C before completely evaluating all the other options, congratulations, you have attained a proper feel of GMAT CR questions.

However, the main rule of CR is: premise is king.

The premise in clear words states that the study is controlled in the aspects of age, weight, general health, exercise.
A control in a scientific study is done to omit outside factors from affecting desirable results. eg: I want to check whether TTP, e-gmat, Anaprep, Magoosh or Manhattan is better. I will have 5 people of identical mental, physical, environmental and all other external factors to go through these courses and graph out the results. That is what control in a study means.

Why I called this simple was because, while doing the first reading itself, the passage told me that I would not have to bother myself with options concerning any of the listed factors and voila! I was left with just two, B and D. Now doing as  KarishmaB  did, would surely be the best approach.

Just by following this one rule that CR has, even if you did not have evaluative capabilities, in this question and some other good ones, you could end up with a choice between 2 competing options, which are much better odds than the current 30% correct rate this question has as of now.

SmileAndSolve · Answer

Study Group: adults over fifty years old who spent an average of four to eleven hours a day sitting

Observation: mortality rates of those who spent less time sitting were consistently lower over three years - even after controlling for age, weight, general health, and exercise frequency, all of which affect mortality rates

conclusion: most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting.

True only if majority population in 4-11 sitting cycle group. Hence, D

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kanikaa9 · Answer

Conclusion is :  most  adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting.

The stem asks: In order to assess the strength of the researchers' reasoning, it would be most helpful to know whether  most adults over fifty years old

Correct  D) spend at least four hours a day sitting -  If Yes  - then it is strengthened - if most i.e. more than half or more than 50% of the people spent >= 4 hrs a day sitting, then only most (> 50%) adults will be able to lower their mortality

If no , then let's say only 1% adults sit for more than 4 hrs a day, then only 1%will be able to reduce the mortality risk.

Raman109 · Answer

A large-scale study of adults over fifty years old who spent an average of four to eleven hours a day sitting found that the mortality rates of those who spent less time sitting were consistently lower over three years - even after controlling for age, weight, general health, and exercise frequency, all of which affect mortality rates. The researchers concluded that most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting.

We do one study and then we generalize that study for most adults over 50. The study focusses on the people who spend an average of 4 to 11 hours. But how about the people who spend less than 4 hrs or more then 11 hrs. They are not part of the study.

In order to assess the strength of the researchers' reasoning, it would be most helpful to know whether most adults over fifty years old

A) who spend less time sitting exercise more frequently - No. This has been accounted for already.

B) spend less than eleven hours a day sitting - They can benefit from this either way.

C) who are in poorer general health are therefore inclined to spend more time sitting - No. General health has been accounted for already.

D) spend at least four hours a day sitting - This is important because if most adults spend less than 4 hours say 1 hr. even no hr sitting, how can they reduce their mortality rate by sitting less when they are already sitting less.

E) who participated in the study were approximately consistent in the numbers of hour they spent sitting each day - consistency is out of scope. We need between average 4 to 11 hrs.

anushkatew · Answer

Could someone please help me - confused even after reading the explanations!!

I want to understand why we are assuming that if someone sits more than 11 hours, then reducing their sitting hours would still help them?

Assume someone sits for 15 hrs a day. Reducing sitting hours by one or two hours may have NO EFFECT on their health? They may be too unfit for it to show much improvement. Don’t understand how we can apply the logic that people under 3 hrs sitting are out of scope but those over 11 hrs are not ?!

errorsapiente · Answer

1. I agree with your logic
2. Another possiblity is that if someone sits for more than 11 hours perhaps their body could enter a state that negates the negatives of sitting i.e the correlation between sitting long and mortality fails to hold past 11 hours (you can't extrapolate)
3. I think that perhaps the reasoning to why option B is not the correct answer is because as MartyMurray pointed out the text says  less than 11 hours  which means it could include 11 hours
4. I don't think E is completely out of scope. The standard deviation of the hours is something to consider:

Suppose David sits:
 
  Day 1:  2 hours 
  Day 2:  20 hours 
  Day 3:  1 hour 
  Day 4:  19 hours 
  Day 5:  3 hours
  Average = 9 hours , which falls in the “high sitting → higher mortality” group.

Suppose Alex sits:
 
  Day 1:  10 hours 
  Day 2:  8 hours 
  Day 3:  9 hour 
  Day 4:  10 hours 
  Day 5:  8 hours
  Average = 9 hours , which falls in the “high sitting → higher mortality” group.

But you can’t assume the negative effects of high sitting apply to David in the same way they apply to Alex.

**I have a hard time with verbal questions because I overthink them, please someone tell me why im wrong**

DevamIIFL · Answer

The top expert to this "hardest question" (one of, at least) has confused me a bit.

A and C are not the answers simply because those factors were controlled with specific mention - they should be eliminated immediately and every other reason is subjective + unnecessary. 
That leaves B, D, E. 
I agree with the reasoning for E - I have the same opinion. 
That leaves B and D.

But again, the logic stated that between B and D the answer B ALSO includes the eleven hour mark. This feels very weak to me. If the researchers' reasoning that we are trying to assess specifically applies to "The researchers concluded that most adults over fifty years old could lower their mortality risk over the next three years just by spending less time sitting." Then people sitting for eleven hours would be those sitting for long times and therefore hardly even related to the conclusion. A situation on a specific group of people is addressed in B by ensuring that only that group of people is being assessed, whereas D introduces a new group of people that aren't even trying to enact our conclusion.
Of course, I'm hardly an expert but I just thought it was way more confusing to read the top solution than just figure out the answer myself.

A large-scale study of adults over fifty years old who spent an averag

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GMAT Critical Reasoning (CR) Questions

A large-scale study of adults over fifty years old who spent an averag

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