Motorcycle-safety courses, offered by a number of organizations, teach

We are told that 92% of the motorcyclists involved in serious accidents (NOT 92% of ALL motorcyclists) have never taken a safety course. This also means that 8% of those involved in serious accidents HAVE taken a safety course.

Before we dig into choice (A), pretend that half of ALL motorcyclists took a safety course and the other half did not. In that case, consider the following possible results from the data:

• Half of motorcyclists involved in serious accidents took the course and half did not (an even split) - this would suggest that the course had no effect. Motorcyclists who took a safety course were just as likely to get in a serious accident as motorcyclists who did not take a safety course.
• Most motorcyclists involved in serious accidents did NOT take the course - this would suggest that the course did help. Motorcyclists who did not take the course were MORE likely to get in a serious accident.

Now, what if only 8% of all motorcyclists have taken a safety course? Well, if the course was useless, then we would expect that 8% of those involved in serious accidents have taken the course. It would be like if we painted blue nail polish on 8% of all motorcyclists. If the nail polish has no effect on safety, then we would expect 8% of those involved in serious accidents to have blue nail polish. In other words, those with blue nail polish are just as likely to be involved in a serious accident as those without blue nail polish.

Similarly, if only 8% of motorcyclists have taken a safety course, then this would suggest that the safety courses did NOT have a significant effect on safety, hurting the argument. However, if significantly more than eight percent of motorcyclists have taken a motorcycle-safety course, then the data would suggest that the safety courses were effective.

Thus, choice (A) is the best answer.
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92% of the motorcyclists who are involved in a serious motorcycle accident have never taken a motorcycle-safety course.
These courses teach important safety techniques.

Conclusion: If more motorcyclists took these courses, there would be fewer serious motorcycle accidents.

This is a useful to evaluate question - what would help us figure out whether the data cited supports our conclusion.
The data cited just tells us that 92% of motorcyclists who were in serious accidents had not taken the course. Using this, it is urging us that all motorcyclists should take the course. What we need to know is how many of those who are not in an accident took the course.

Say 1000 people ride motorcycles.
Say there were 100 serious accidents in the year. We know that of these 100, 92 have not taken the course and 8 have.
So 900 people did not have any serious accident.

Now what if we find out that out of the remaining 900 people, none had taken the course? It seems that the course teaches something that is causing accidents!! Does it support our conclusion of taking the course - NO

What if we were to find out that of the remaining 900 people, 400 had taken the course? Now it seems that the course did make people follow safety rules. Among non-accident people, a large number had taken the course while among the accident-people, very few had taken the course.

This is what option (A) says.

(A) Whether significantly more than eight percent of motorcyclists have taken a motorcycle-safety course
If overall, much higher percentage of the people take the course then it makes sense that the course helps. If overall only 8% people (or even lower) take the course, the number of 92 is what we would expect anyway so taking the course would not have helped.

All other options are irrelevant.

Answer (A)
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This is an evaluate question. We need to identify the central assumption and find an answer choice that, when answered, would either strengthen or weaken the conclusion.

The argument is: Because 92% of motorcyclists involved in bad motorcycle accidents have never taken a safety course (evidence), there would be fewer bad motorcycle accidents if more motorcyclists took safety courses (conclusion).

A shift in scope underpins the central assumption: that motorcyclists involved in bad motorcycle accidents (the sample) are representative of motorcyclists in general (the group). We have data on the sample (92% don't have training), but we need a way to compare that data to similar data for the group as a whole.

So we can expect that the answer will address the sample's representativeness in some way.

A - Correct. If significantly more than 8% of motorcyclists in general (the group) have taken a safety course, we can then compare that to the implied 8% of the sample who have taken a safety course. For instance, if 25% of the group has taken a safety course, but only 8% of the sample has taken a safety course, then there's a strong negative correlation between motorcyclists who have taken safety courses and those who have been involved in bad accidents. This strengthens the argument. Now let's say that only 1% of the group has taken a safety course; that means that there's a strong positive correlation between motorcyclists who have taken safety courses and those who have been involved in bad accidents. This weakens the argument.
B - Out of scope; argument says nothing about passengers
C - Also out of scope; we're not interested in comparing between different safety courses.
D - A few previous posters selected this, so let's puzzle it out. It mentions the 92% proportion and so might address representativeness--but it only mentions the 92% in connection with collisions with other vehicles in motion, which is irrelevant. Note that we're no longer talking about the 92% of motorcyclists involved in bad accidents without training; we're talking about 92% of all bad accidents. This is a shift in scope.
E - Also out of scope; we're not interested in the influence of size/speed, but taking vs. not-taking a safety course

A, I have my reasoning based on statistics that i can see.

Here it goes, The argument asks us to evaluate the data that "92 percent of serious accidents involve people who did not have training" and its impact on the argument. So the obvious question that arises is: Whether that number 92 percent is also equal to the number of people who are not trained and if that is the case then stats do not show anything surprising. But if on the other hand lets say that 90 percent of people are trained and rest 10 percent are not trained and only the 10 percent are involved in accident then the data does not help.

Will explain more if thinking is correct.
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Applying the variance test we can simply check the validity of the conclusion and reach at the correct answer in " evaluate the argument " type of questions.. here we need to swing the conclusion " if more motorcyclists took this course , there would be fewer motorcycle accidents...Clearly A is the correct choice here ..

As option A says.. Whether significantly more than 8% of motorcyclists in general (the group) have taken a safety course..

If we answer No to his question and assume that may be only 8% or 9% of motorcyclist have taken the safety course ..it clearly strengthens the conclusion ..As motorcyclist not involved in accidents is 8% and if all of them have taken a safety course or if only 1% of those who have taken the course met with an accident then the argument conclusion is obviously strengthened .. as those who are taking the course are not involved in accident , thus if more people took this course lesser accidents..

If we answer yes to the option A i.e significantly higher than 8% of that group has taken the course ..assume 50%..this means that lots of motorcyclists who took the course still met with an accident coz only 8% did not meet an accident ..so may be 42% of those who took the course met with an accident ..so clearly conclusion is weakened ..as the course does not guarantee lesser accidents..

Answer D is clearly a TRAP! It creates a confusion on stats presented: "92% of people involved in serious accidents didn't take course" is different than "92% of people involved in serious accidents with other vehicles".

IMO A.

Here,

Conclusion: If more motorcyclists took motorcycle-safety driving courses, there would be fewer accidents (Cause-effect relation)
Evidence: 92% of the motorcyclists involved in the accidents had never taken any motorcycle-safety driving course.

Pre-Thinking:
The argument basically says that evaluate this sample statistical evidence i.e. whether indeed this represents the above mentioned causal relation. Immediate doubt should come what if the sample itself contained more motorcyclists without any motorcycle-safety course i.e. data is misrepresented and skewed towards proving the causal relation itself.

We need to analyze whether remaining 8% of the motorcyclists of the statistical evidence truly represents the motorcyclists with motorcycle-safety course or they are underestimated.

The correct answer should re-phrase this. A allows us to this rephrasing and evaluation of the argument and causal relation.

B. Irrelevant as we are not concerned about the risk of driving alone or with any other person accompanied.
C. Simply Out of Scope.
D too is irrelevant here since looking at it closely we can see that this option fails to prove and evaluate the causal relation here.
E. Irrelevant. It doesn't address the conclusion or rather causal relation. Size and speed are irrelevant.

Hence IMO A.
Please provide the OA. Really good question.

I think answer should have been phrased more precisely.

Cause : Courses
Effect: fewer serious accidents

Data: 92%(of serious accidents) didn't take course.

Assume 100 accidents

92 didn't take course
8 took course.

Now by this data author concludes that courses-> few accidents.

However,we don't have data about how many of total motorcyclists had courses.

If 1000 took course and only 8 met with accident then course is fruitful.

If 8 took course and 8 met with the accident, then course is not fruitful.

LET Y NUMBER OF SERIOUS ACCIDENTS........
0.08Y ARE TRAINED, 0.92Y ARE NOT TRAINED

FIRST SCENARIO......LET X MOTORCYCLYSTS------
.09X HAVE TRAINED, .91 X HAVE NOT

RATIO OF ACCIDENT-----TRAINED- .08Y/.09X= 8Y/9X ........UNTRAINED- 0.92Y/0.91X=92Y/91X........TRAINING IS USEFUL

SECOND SCENARIO---........07 X TRAINED, .93X DID NOT..................

RATIO OF ACCIDENT...... TRAINED- 8X/7Y.......UNTRAINED- 92Y/93X............TRAINING IS NOT USEFUL


"A"IS THE CORRECT ANSWER...........


KUDOS IF YOU PLEASE.............

Motorcycle-safety courses, offered by a number of organizations, teach motorcyclists important techniques for handling and for safely sharing the road with other road users. If more motorcyclists took these courses, there would be fewer serious motorcycle accidents. Data show that 92% of the motorcyclists who are involved in a serious motorcycle accident have never taken a motorcycle-safety course.

In assessing whether the data cited provided support for the position taken about motorcyclists' taking the courses, it would be most useful to determine which of the following?

- Whether significantly more than eight percent of motorcyclists have taken a motorcycle-safety course -> Correct
92% didn't take the course and suppose 8% have taken the course who were not involve the accident -> Supports the argument
Suppose only 1% out of 8% who have taken the course were not involved in the accident. Then there is some other reason for this observation-> Weakens the argument

- Whether it is riskier for a motorcyclist to ride with a passenger behind the rider than to ride alone - OFS
- Whether the different organizations that offer motorcycle-safety courses differ in the content of the courses that they offer - OFS
- Whether more than 92% of serious motorcycle accidents involve collisions between a motorcycle and another vehicle in motion. - OFS
Serious accidents is a subset of accidents caused by the issues addressed in the courses. The premise has already mentioned that. It is irrelevant to mention it again.
- Whether variations in the size and potential speed of a motorcycle influence the risk of a serious accident's occurring. - OFS
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The data talks about [part] drivers who were involved in accidents, but the argument makes conclusion about [whole] all drivers.

100 drivers met with an accident
92 drivers did not take the course
8 drivers took the course but still met with an accident

to evaluate the argument we need to find a relation between the subset and the whole group.

1000 drivers
say 8 % took the course and 92% did not

then 80 took the course - out of 80 drivers, 8 met with an accident. this percentage is 8/80 = 10%
920 did not take the course - out of 920 drivers, 92 met with an accident. this percentage is again 10%.
This weakens the argument.

similarly, we can take the other extreme and show that it strengthens the argument.

Thus A is the correct choice.

i find that i got trapped since argument speaks about motorcyclists who are involved in a serious accident, and answer choice talks about all motorcyclists, so i ruled it out as comparing two different subsets of data.

So to that, is it just a poorly written question or is it like that on purpose? and if on purpose, how do u reconcile comparing two subsets of data?

First of all, you need to understand the pattern how GMAT is testing you. For example %centages - normally GMAT tests the students:
1) Comparing %tages and actual Numbers
2) Changing the base of the %tages

So this question falls in the second category and as a student, you need to understand that change and be mindful of these changes.

This is not at all poorly written question and you need to practice more these type of questions to get a hang of these questions.

All the best.

Hi everybody,

This question is such a masterpiece that I thought I should post my 2 cents for those who still didn't get what the Q is basically talking about.

Pls refer the figure I attached:
Case I is the situation presented in the Q i.e. it represents the motorcyclists involved in a serious motorcycle accident
Case II and III represents those motorcyclists who NEVER involved in a serious motorcycle accident

Firstly, we have to consider those motorcyclists too who NEVER involved in a serious motorcycle accident, in order to recommend that the course would basically reduce the no. of serious motorcycle accidents.

Now, look at hypothetical case II, in which we see that only 9% motorcyclists took the course and the rest 91% didn't care. In this situation can we really say that more the motorcyclists take the course less the no. of serious accidents. NO, it seems the courses actually do not any role to prevent motorcyclists from serious accidents. So, conclusion doesn't hold here.

Now consider hypothetical case III, clearly the training made the difference here and we should recommend the course. In other words the conclusion is true. Note that for the case III to be true, overall, significantly more than eight percent of motorcyclists have taken a motorcycle-safety course. This is nothing but choice A.

I know we can't afford to think or draw in such details during GMAT but, this is to show you the level of thinking required by this kind of Qs. I prefer diagrams over words, so it was easy for me to think this way. Experts, pls correct my mistakes.



P.S. Sorry for the totally unprofessional diagram :wink:

Now frankly speaking i think this question is overrated

I saw the difficulty level to be 85% and was over cautious while reading. Then i came to option A and spent good time there. I moved even without comprehending it 100%. But as soon as i read the other choices, i realized that all others were too distant from the topic at hand and hence are all either irrelevant or out of scope. I had my variance test ready, but never needed to use. Am i missing anything?

D has got the most votes! Why would we care about what the motorcycle has hit- a moving motorcycle,a truck ,a wall or anything for that sake. That's completely irrelevant. I mean.. seriously whats the catch that im missing?!?

I got this question wrong when taking GmatPrep, but I honestly believe that understanding why we might select wrong answers helps us learn to make correct choices in the future.

I initially chose answer choice (D) when taking GmatPrep exam 1. When reading the question, I summarized the argument as follows: more cyclists taking courses will lead to fewer accidents. I then attempted to find an answer that would indicate this statement wasn't true.

I summarized answer choice (D) as:

If 92% of accidents involve someone else then there is the possibility that even if motorcyclists take course the number of accidents might not be reduced because we don't know anything about the behavior of other drivers. Admittedly, my logic here was wishy washy because we don't know for sure that the course still wouldn't help in this case. An evaluate answer must be one such that either an answer of "YES" or "No" either strengthens or weakens the argument. One caveat here that I feel isn't mentioned a lot is that the answer doesn't have to both strengthen and weaken. If an answer of "YES" strengthens, but an answer of "No" doesn't tell us much then the answer could still be correct.

With that said, I think one of the biggest mistakes here is that I was looking for an answer that weakened my summary of the argument above (courses -> fewer accidents). However, the question is not asking for something that would just weaken the argument. The argument is asking for something that evaluates the validity of evidence. This type of question is a little unusual for me personally.

The only answer choice that directly challenges the validity of the data itself is answer choice A. As someone already pointed out, answer choice D focus on 92% of "Accidents" instead of 92% of motorcyclists in accidents.

I realize my response might not be as profound as some others on this thread but I hope it was helpful to anyone who had a similar thought process as I did when answering this question.

Although I marked D as an answer, I had a little hard time understanding A as an answer. The number approach below helped -

Suppose, there are 200 motorists, and among those, 100 are involved in accidents.
This implies, 92% of 100, i.e. 92 motorists who were involved in accidents did not took the safety course. Also, remaining 8 motorists did.

Now, among total 200 motorists did more then 8% of motorists took safety course -->

YES - that means more than 8%=16 motorists, lets take 17. This means 17 motorists took the course and among those, 8 were involved in accidents, which is less than 50% of people who took safety course. This implies safety course did help majority motorists (=9) avoid accidents.

NO - that means less than 8%=16 motorists, lets take 15. This means 15 motorists took the course and among those, 8 were involved in accidents, which is MORE than 50% of people who took safety course. This implies safety course did NOT help majority avoid accidents.

Therefore its important to get an answer for A to support safety course.
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Hello Verbal Experts (GMATNinja,e-Gmat)

I am confused how option A is the answer?

Can someone help over here..

Thanks in advance!

Motorcycle-safety courses, offered by a number of organizations, teach motorcyclists important techniques for handling their vehicles and for safely sharing the road with other road users. If more motorcyclists took these courses, there would be fewer serious motorcycle accidents. Data show that 92 percent of the motorcyclists who are involved in a serious motorcycle accident have never taken a motorcycle-safety course.

In assessing whether the data cited provide support for the position taken about more motorcyclists’ taking the courses, it would be most useful to determine which of the following?

Cool, question is asking for what will be helpful to determine the blue above

A) Whether significantly more than eight percent of motorcyclists have taken a motorcycle-safety course Maybe. Leave it on side. No reason to reject
B) Whether it is riskier for a motorcyclist to ride with a passenger behind the rider than to ride alone Too much implied and not enough mentioned in stem. This is overthinking it. Reject
C) Whether the different organizations that offer motorcycle-safety courses differ in the content of the courses that they offer Nothing in the stem talks about different courses. Reject.
D) Whether more than 92 percent of serious motorcycle accidents involve collisions between a motorcycle and another vehicle in motion So what is it's with a crash against a pavement or another vehicle? I don't see how this is relevant.
E) Whether variations in the size and potential speed of a motorcycle influence the risk of a serious accident’s occurring Same as above, no information is provided about size and speed of a motorcycle in the stem or in the course

Via POE, I would choose A.