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

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