In Wareland last year, 16 percent of licensed drivers under 21 and 11

A beautiful GMAT question for which I promise you is EASY, but you have to really, really understand what the stimulus says and what the answer choices say. You must be careful when answering, let's attack it.

Which of the following is an assumption on which the argument depends?

(A) Drivers 65 and older do not, on average, drive very many fewer miles per year than drivers 24 and younger.

If drivers 65 and older don't drive fewer miles as a percentage of the overall group, than do drivers 24 and younger, then we can assume that drivers 65 and older are on the road just as frequently or as long as drivers 24 and under are. This actually follows the logic of the argument. Lets keep this one and come back to revisit it.

(B) Drivers 65 and older do not constitute a significantly larger percentage of licensed drivers in Wareland than drivers ages 18-24 do.

The author actually wrote that the these statistics were written as a percentage of their respective groups. Thus, the author already confirmed the fact that the argument is disregarding the actual number of drivers of each category on the road as a result of comparing the two percentages and not the absolute values.

(C) Drivers 65 and older are less likely than are drivers 24 and younger to drive during weather conditions that greatly increase the risk of accidents.

While this may be true, we don't have enough information from the stimulus to determine what effect this has on the actual percentages. While attractive, one has to realize that there is no real merit to this assumption as a result of the author's argument because of the lack of information in the stimulus. What can we really conclusively determine from this?

(D) The difference between the accident rate of drivers under 21 and of those ages 21-24 is attributable to the greater driving experience of those in the older group.

While this may be true and does in fact follow the argument, this is not a required assumption to arrive at the author's argument that those who are 65 or older have more experience and thus have less accidents. We're interested in a comparison between those 65 and older and those 24 and under.

(E) There is no age bracket for which the accident rate is lower than it is for licensed drivers 65 and older.

While this answer choice, also, may be true and thusly would follow the author's argument, it is not a requirement for the argument. There could be an age group, for example, drivers age 50-65 who if they had an even lower percentage than those 65 or older, there could be alternative factors (sight, reflexes) that could also explain why those age 65 or older could have a higher accident rate than those 50-65, while still maintaining a higher level of experience. This is not a required assumption.

Dear ChiranjeevSingh GMATNinja

I understand that why option A is correct and perfect.
But I wanted to clarify certain aspect about Option E.

Is the author of the question in the Conclusion alluding to the younger drivers( colored Red) to be the Same or younger drivers in general than the 65-and-older group?

In Wareland last year, 16 percent of licensed drivers under 21 and 11 percent of drivers ages 21-24 were in serious accidents. By contrast, only 3 percent of licensed drivers 65 and older were involved in serious accidents. These figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

Which of the following is an assumption on which the argument depends?

(E) There is no age bracket for which the accident rate is lower than it is for licensed drivers 65 and older.

Case 1:If the author of the question is alluding to the colored younger drivers then the E option is incorrect.

Case 2: If the author of the question is alluding to younger drivers in general than the 65-and-older group
Say a Case that a group between 35-40 has accident rate of 1 percent.

Then Doesn't the below conclusion breaks?
These figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

Case 2 breaks the above blue colored part thereby breaking the complete conclusion?

Could you please enlighten?

Even if we take it to be "younger drivers in general" i.e. drivers less than 65 years of age, option E still doesn't break down the argument since the age bracket for which the accident rate is lower could be of people, let's say, aged 80 and over. So, there exist situations in which the argument holds even in the face of negation of the option.

- CJ

Dear ChiranjeevSingh

Thank you for your reply!

I still have a doubt about your example:
Sir in below option E it is mentioned as
There is no age bracket for which the accident rate is lower than it is for licensed drivers 65 and older..

Doesn't the group 65 and older. covers all those older than 65. and If a certain group younger than them has least accident rate then doesn't that breaks the conclusion when case is of "younger drivers in general" i.e. drivers less than 65 years of age,

Conclusion:
These figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

Good question! I was actually thinking of writing about this aspect while posting. However, I decided that I'd write about this if you asked a doubt. And here I am

You are right: 65 years and older includes 80 years and older. However, just because I have created an age bracket 65 and older doesn't mean that I cannot create an age bracket 80 years and older. Rather, it's pretty common to talk in terms of overlapping sets in many contexts. For example: the average property prices in the US are lower than the average property prices in New York. The comparison makes sense even though New York is a part of the US. Similarly, the accident rate for the age group 65 years and older may be higher than that for the age group 80 years and older.

GMATNinja

the dreaded option E.....

option A ensures that the percentages given are comparisons of similar driving times.

my question is: in absence of A, wd E be the correct choice?

one way to look at is the TREND: the percentage of accidents seem to be a declining trend so one cd argue that between 24-65 the percentages wd continue to fall

which brings me to the question.....is it correct to assume there IS a trend?

Pre-Thinking what author is saying:
1.) presents some figures.
2.) Conclusion: greater experience and developed habits are the reason, why the 65+ year olds have such a low accident rate.

What did the author assume to draw that conclusion?
That 65+ year olds have " greater experience and developed habits" in the first place. Only then would that conclusion make sense.


(A) Drivers 65 and older do not, on average, drive very many fewer miles per year than drivers 24 and younger.
Expl: Wordy, but hits the point. The author assumes that 65+ year olds have greater experience, therefore the assumption that 65+ year olds drive at least as much as 24-and-younger-ones do, is pretty much what we want.
There still could be a better answer choice which says that 65+ year olds definitely have better experience or smth.....so keep looking. But hold A) for now.
Good choice so far!

(B) Drivers 65 and older do not constitute a significantly larger percentage of licensed drivers in Wareland than drivers ages 18-24 do.
Expl: Quick look back at the figures tells us, that the figures are already in percent. So if 65+ year olds would make up a larger percentage, still only 3 percent would be involved in accidents.
Assumptions on percentages would have absolutely no effect because of that. Also, the author is saying nothing that would be attributable to a lesser/larger percentage of licensed drivers of a group.
Incorrect.

(C) Drivers 65 and older are less likely than are drivers 24 and younger to drive during weather conditions that greatly increase the risk of accidents.
Expl: One may could be tempted by this answer. Because we are looking for an assumption that states that 65+ year olds have more experience.
But this answer choice here goes one step further and says that 65+ year olds definitely drive less on bad weather conditions. We cannot necessarily say that. we have to be strict.
Incorrect.

(D) The difference between the accident rate of drivers under 21 and of those ages 21-24 is attributable to the greater driving experience of those in the older group.
Expl: Another more tempting answer choice. in a general term it says, the author assumes that difference in accident rate between age groups is attributable to greater driving experience.
Which sounds to be in the line of reasoning of the author. But look closely, thats all there is to it.
First, why is it so specific about the younger two groups? Could be better if it talks about two groups involving those 65+ year olds, since we are talking about them.
Secondly, and more importantly, this just restates the conclusion. Not what the author assumes. It just restates the conclusion that difference in accident rates is because of the better driving experience. GMAT never asks in Assumption-Questions for answer choices that just restate what the author is saying. Thats not an unstated assumption. those restatements can not be correct in assumption questions!!!
Incorrect.

(E) There is no age bracket for which the accident rate is lower than it is for licensed drivers 65 and older.
Expl: Does the author assume that in order to draw his conclusion? Does the author assume that the accident rate is lowest for 65+ year olds in order to draw the conclusion that they have such low accident rates because of their better experience? Think about it..... No!
Incorrect.

Only A) is left, make your move then.

Remember, the conclusion of this argument is, "These figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than younger drivers are."

This post explains why it's so important to take this conclusion exactly as it's written.

Additionally, the question asks which choice is an assumption on which the argument depends. So in our process of elimination, we need to determine whether each answer choice is an assumption that MUST be true for this specific conclusion to be valid.

In the same post I linked to above, I've explained here why choice (E) is NOT a required assumption (the accident rate of licensed drivers 65 and older has no impact on the argument the author is making).

If (A) were not one of the choices, we would still eliminate (E), because on its own merits, this choice is not required for the conclusion to be valid.

I hope this helps!

Passage Analysis

• In Wareland last year, 16 percent of licensed drivers under 21 and 11 percent of drivers ages 21-24 were in serious accidents.

o The statistics presented are data about accidents that happened in Wareland the previous year.
o It has been observed that 16% of licensed drivers of the age group below 21 years were involved in serious accidents.
o The share of licensed drivers in serious accidents drops to 11% for the age group from 21 years to 24 years.

• By contrast, only 3 percent of licensed drivers 65 and older were involved in serious accidents.

o On the other hand, the fraction of licensed drivers older than 65 who were part of serious accidents was as small as 3 percent.

• These figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

o The author concludes that the data illustrates that the higher level of experience and developed habit of vigilance that the drivers above 65 years have, make them a safer choice to be drivers when compared to younger people.

Conclusion: The figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

Question Stem Analysis
We are required to find the assumption necessary for the argument to hold.

Pre-thinking

Falsification Question
In what scenario is it possible that the figures do not show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are?
Given that

• In Wareland last year, 16 percent of licensed drivers under 21 and 11 percent of drivers ages 21-24 were in serious accidents.
• Only 3 percent of licensed drivers 65 and older were involved in serious accidents.

Thought Process
The statistics presented compares the involvement of licensed drivers belonging to various age groups, in serious accidents. The author concludes that the low rate of serious accidents amongst the senior-most drivers as compared to the youngest lot is due to the older ones’ greater experience and habit of caution. While the metrics put forward by the data are quite straight-forward, some factors like the actual amount of travelling done by the compared groups and the possibility of other factors for being the major reason of this contrast should also be examined.

Falsification Condition#1
The probability of being involved in a serious accident increases with the distance and time one spends driving. What if the distance and time drivers 65 years and older spent behind the wheels is very low compared to the young drivers? In that case, any conclusion by drawing from the data available becomes baseless.
Assumption#1
The distance and time drivers 65 years and older spent behind the wheels is not very low compared to the young drivers.

Falsification Condition #2
What if there are factors other than the experience and caution that causes drivers of the older age group to have lesser accidents? For example, not being able to drive as fast as young drivers due to physiological limitations. Here too the premises hold but the conclusion does not.
Assumption#2
There are no other factors more significant than the experience and caution that causes drivers of the older age group to have lesser accidents.

Answer Choice Analysis

(A) Drivers 65 and older do not, on average, drive very many fewer miles per year than drivers 24 and younger.
CORRECT
This option is in line with our pre-thinking and hence the correct answer choice.

(B) Drivers 65 and older do not constitute a significantly larger percentage of licensed drivers in Wareland than drivers ages 18-24 do.
INCORRECT
The absolute number of drivers in each group need not be a large percentage of the total pool of licensed drivers. What matters is the amount of travelling done by the members of each group. Hence this is not the correct choice.

(C) Drivers 65 and older are less likely than are drivers 24 and younger to drive during weather conditions that greatly increase the risk of accidents.
INCORRECT
This statement may be true but it is not an assumption necessary for the conclusion to hold. Hence this is not the correct answer choice.

(D) The difference between the accident rate of drivers under 21 and of those ages 21-24 is attributable to the greater driving experience of those in the older group.
INCORRECT
This statement may perhaps be true, but the difference in the level of experience between the two age groups is very little for us to be sure of the validity of this assumption. In any case, this assumption is not necessary to compare the youngest and oldest groups of drivers. Hence, this too is an incorrect answer choice.

(E) There is no age bracket for which the accident rate is lower than it is for licensed drivers 65 and older.
INCORRECT
It is possible that the age group between 61 and 65 also exhibits accident rates as low as the group above 65. They may even show a lower rate of accidents as they are likely to possess better eyesight and quicker reflexes. But this does not negate the conclusion made comparing very young drivers to 65 plus years old drivers. Hence, this is an incorrect answer choice as well.

VeritasKarishma

can option C acts as strengthener

As conclusion mentions greater experience and developed habits of caution possessed by drivers in the 65-and-older group

so it's telling that older people take precautions of less driving in harsh weather conditions

Option (C) doesn't add a whole lot to the argument. It only gives an example of a developed habit of caution. Whether an option can be a strengthener depends on how it is worded and what the other options are in an actual question. all we can say for sure is that option (C) is not the assumption in this question.

I am confused between A and D. I would request you to please elaborate on how D is not a correct option.

Many thanks in advance

Hi Rahul

The conclusion is regarding the experience and caution of drivers over 65 causing fewer accidents. Option (D) merely suggests that greater experience of the 21-24 age group causes fewer accidents. It is possible that this factor does not play any role (or any incremental role) when a person reaches the age of 65 years. The option does not address the demographic mentioned in the conclusion at all and hence cannot be an underlying assumption.

Hope this helps.

Srini

Let’s look at the premises and conclusion of the given argument.

Premises- In Wareland last year, 16 percent of licensed drivers under 21 and 11 percent of drivers ages 21-24 were in serious accidents. By contrast, only 3 percent of licensed drivers 65 and older were involved in serious accidents.

Conclusion- These figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

(A) Drivers 65 and older do not, on average, drive very many fewer miles per year than drivers 24 and younger.

Let’s negate A and see if there’s an impact on the conclusion-
Drivers 65 and older, on average, drive very many fewer miles per year than drivers 24 and younger.

If this were the case, then we are bringing in another reason why only 3 percent of licensed drivers 65 and older were involved in serious accidents- because they drive fewer miles!
Negation of A breaks the argument. Correct.


(B) Drivers 65 and older do not constitute a significantly larger percentage of licensed drivers in Wareland than drivers ages 18-24 do.

Let’s negate B- Drivers 65 and older constitute a significantly larger percentage of licensed drivers in Wareland than drivers ages 18-24 do.

As the data tells us the percentage of drivers involved in serious accidents, the number of drivers that constitute a larger percentage of licensed drivers does not impact the argument. Eliminate.

(C) Drivers 65 and older are less likely than are drivers 24 and younger to drive during weather conditions that greatly increase the risk of accidents.
C brings in another reason- weather conditions that increase the risk of accidents- Breaks the conclusion.
The conclusion is that greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.
Eliminate


(D) The difference between the accident rate of drivers under 21 and of those ages 21-24 is attributable to the greater driving experience of those in the older group.
The comparison is between younger drivers (under 21 and 21-14) and older drivers( 65 and older). Option D is comparing drivers within the group of younger drivers. Irrelevant to the conclusion. Eliminate.


(E) There is no age bracket for which the accident rate is lower than it is for licensed drivers 65 and older.

Let’s negate E- There is an age bracket for which the accident rate is lower than it is for licensed drivers 65 and older.
The conclusion is just that- greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

Negation of E does not impact the conclusion. Eliminate.

VP
GMAT SME

GMATNinja egmat - how do I go about rejecting choice C? How I read is that this choice explains how because of greater experience the older drivers have fewer accidents since they do not venture out in conditions that will not lead to accidents.
this I think reinforces the conclusion. Please tell me where I am going wrong?

- Fatima

Let's start by identifying the conclusion: the greater experience and caution of drivers 65-and-older makes them "far safer behind the wheel" than younger drivers. This conclusion is based on the fact that "only 3 percent of licensed drivers 65 and older were involved in serious accidents," while the percentage was considerably higher for younger drivers.

This question is asking for an assumption "on which the argument depends." So the correct answer should be both supportive of the argument AND necessary to draw the conclusion.

Let's consider (C):

So the question is: is this statement necessary to draw the conclusion?

Well, what if it weren't true? What if drivers 65 and older were equally likely as younger folks to drive during "weather conditions that greatly increase the risk of accidents?" Would that mess up the argument? Not really.

Keep in mind that we already know that a smaller percentage of drivers 65 and older get in serious accidents. So if they drove in dangerous conditions just as frequently as younger drivers, but a smaller percentage got in serious accidents, that would support the idea that they are safer behind the wheel. Because even if older drivers ventured out in dangerous weather just as often as younger folks, we already know the percentage getting in serious accidents is smaller (i.e only 3 percent, compared 11% or 16% for younger drivers).

So even if statement (C) were NOT true, the argument would still hold, so it can't be necessary. And if it's not necessary, it's not an assumption on which the argument depends, and (C) is out.

I hope that helps!

A lot of experts have already pitched in on why C or E would not be the answer. Ill try to add a little bit more to it.

In Wareland last year, 16 percent of licensed drivers under 21 and 11 percent of drivers ages 21-24 were in serious accidents. By contrast, only 3 percent of licensed drivers 65 and older were involved in serious accidents. These figures clearly show that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

Flow of the para: As per stat on % of certain age group of drivers involved in serious accidents, it is concluded that the greater experience and developed habits of caution possessed by drivers in the 65-and-older group make them far safer behind the wheel than the younger drivers are.

Always make note of each word as it may give you the reason to eliminate a wrong choice.

Which of the following is an assumption on which the argument depends?


A strong contender from the very word go. You will find some other questions too with same logic/reasoning.
What if 65+ drivers drive just 10 miles a day on an average as compared to 200 miles a day by the younger group?: Very many fewer miles limit the probability or chances of the serious accidents.
Lesser the exposure to such conditions, lesser the chances of accidents.

Had it been opposite, that is, 65+ constituted a significantly larger percentage of licensed drivers in Wareland than drivers ages 18-24 do, the option could actually be a strengthener.
It does not compare the time spent behind the wheel by each group.

Might sound very tempting, but there are enough reasons to discard it.
1) Although none of the replies have spoken about it, I do believe this could be a valid reason to discard it.: The words - safer 'behind the wheels'. So we are comparing the act of driving and not the act of 'avoiding driving'. Yes, it tells us that 65+ are cautious on time to be out on the road, but it really does not tell us about safe driving.
2) 65+ drivers may be avoiding driving during bad weather conditions, but they may be traveling on average more than young group, leading to more exposure.

The group we are comparing 65+ with is 18-24, but this options talks of 21-24 year old drivers.

We cannot be sure and this does not affect the comparison between two groups. 40-50 group may be the safest but it does not help the conclusion in any way.



A