The rise in free, do-it-yourself instructions on the Internet for home

Dear ronr34,
Great question! That's a detail in a gray area --- the argument absolutely would not make sense if those two were not different groups, but technically, we have no explicit guarantee that they are different. Technically, it's the explicit evidence that we have trust, not necessarily the validity of the argument as a whole, although the GMAT always gives a valid argument on an inference question. This is very much in a gray area.
I would say --- something of this sort the GMAT wouldn't touch with a ten-foot pole. It's not quite up to the standard of a right answer for an inference question, but it's far too close to be a wrong answer. The GMAT is very good about giving us one unambiguously right answer and four unambiguously wrong answers. They scrupulously avoid anything in a gray zone.
Does this make sense?
Mike
_________________

A. The number of people who are not home repair technicians and who have been injured while attempting home repairs has increased.
=> INCORRECT. From the stimulus, injured people (X) = non-technicians (Y) + technicians (Z), increase in the number of injured people X can result from the increase of either Y or Z or both Y and Z

B. Most people who are injured while attempting home repairs have done so while following instructions found in free do-it-yourself instructions on the Internet.
=> INCORRECT. The stimulus provides nothing about the link between free instructions and injured people; moreover, X=Y+Z, we assume Y watches the instructions and Z doesn't, we have no information about the rate Y:Z so that we cannot say "most" here. In addition, this answer choice says people was injured "while following", this absolutely wrong.

C. The overall sale of online do-it-yourself home repair instructions by home service technicians has not been equal to the loss of revenue the technicians have incurred due to free offerings of this sort of material.
=> INCORRECT. The stimulus mentions nothing about the sale of online do it urslf, moreover, the loss in revenue may come from a ton of other reasons.

D. Most free do-it-yourself home repair instructions found on the Internet do not provide enough clear information regarding safety precautions.
=>CORRECT. This help to solve the discrepancy the most for the stimulus, the rise free instructions => the increase of the number of injured people and "unfortunately, not all ...".

E. As more free do-it-yourself instructions for home repairs are made available on the Internet, home service technicians will suffer more losses in revenue.
=> INCORRECT. This is very tempting, "infer" means deduce from evidence (https://www.google.com/search?q=inferre ... 8&oe=utf-8); this answer choice is a inductive reasoning prediction in the future "will suffer", this allows this prediction could be true not must be true, but the stimulus is a phenomenon which happened "has led", so the inference must be true.

The rise in free, do-it-yourself instructions on the Internet for home repairs has led to a decrease in revenue for home service technicians and an increase in the number of injuries caused by people who have attempted home repairs themselves. Unfortunately, not all of the do-it-yourself instructions on the Internet are written as well as they should be.

x= attempt to home repair using instructions from internet.

Which of the following can be inferred from the argument above?

A. The number of people who are not home repair technicians and who have been injured while attempting home repairs has increased.
(we do not know if injured people are technicians or not.)

B. Most people who are injured while attempting home repairs have done so while following instructions found in free do-it-yourself instructions on the Internet.
(argument only talks about "number" of people injured by x. We do not know percentage of such people to infer the word "most", as implied in this statement)

C. The overall sale of online do-it-yourself home repair instructions by home service technicians has not been equal to the loss of revenue the technicians have incurred due to free offerings of this sort of material.
(Not very clear at first. Hold on)

D. Most free do-it-yourself home repair instructions found on the Internet do not provide enough clear information regarding safety precautions.
(last line of the argument starts with "not all" and not all <> most, so we cant conclude this. May be there is just one such instruction that do not provide clear information)

E. As more free do-it-yourself instructions for home repairs are made available on the Internet, home service technicians will suffer more losses in revenue.
("will suffer", implies that something will be repeated in future. We only have information on what is happening at present. So cant conclude whether such effect will continue in future)

After elimination C remains.
Now additional thoughts on C:
If home technicians would have been able to sell the instructions on internet and its sales would have been equal to revenue lost in repair service, then overall they would have experienced decrease in revenue at all.

With or without validity of this additional thought C remains by poe.

Dear mcwoodhill,

Remember for inference questions the correct answer choice "MUST BE PRECISELY CORRECT".

Here goes detailed analysis of each answer choice:


(A) The number of people who are not home repair technicians and who have been injured while attempting home repairs has increased

INCORRECT.

Why???

Because there might be the case that number of people might "Do Not Change" or even "Decrease" but number of injuries per person increases.


(B) Most people who are injured while attempting home repairs have done so while following instructions found in free do-it-yourself instructions on the Internet.

INCORRECT.

We can not infer that. There might be other reasons also.

(C) The overall sale of online do-it-yourself home repair instructions by home service technicians has not been equal to the loss of revenue the technicians have incurred due to free offerings of this sort of material.

CORRECT

As mentioned in the argument, this is the reason the revenues are decreasing. This choice simply means that loss of the technicians (because people start using self instructions) has not been compensated by sale of online instructions, which is true.

(D) Most free do-it-yourself home repair instructions found on the Internet do not provide enough clear information regarding safety precautions.

INCORRECT

Argument only mentions "Not All" of the do-it-yourself instructions on the Internet are written as well as they should be. We can not infer "Most" clearly out.


(E) As more free do-it-yourself instructions for home repairs are made available on the Internet, home service technicians will suffer more losses in revenue.

INCORRECT.

It is nothing but a generalized statement.

Hope it helps!


"Please hit +1 Kudos, if the explanation is helpful to you"

mikemcgarry : Hi Sir, sorry to bother you again ...but can you explain this question ...my initial reaction was option C is totally out of scope ...and even after some deliberation I am NOT able to get the logic behind it ...
_________________

Dear mihir0710,

I'm happy to respond.

First of all, I am going to recommend this blog:
GMAT Critical Reasoning: Find the Conclusion or Inference

Look at the prompt:
The rise in free, do-it-yourself instructions on the Internet for home repairs has led to a decrease in revenue for home service technicians and an increase in the number of injuries caused by people who have attempted home repairs themselves. Unfortunately, not all of the do-it-yourself instructions on the Internet are written as well as they should be.
If all this is true, what are some very certain and clear conclusions?
We know there free, do-it-yourself instructions on the Internet for home repairs, and these have been increasing.
We know revenue for home service technicians has declined.
We know the number of injuries caused by people who have attempted home repairs themselves has increased.
We don't know whether these people were following the directions correctly.
We don't know how many of these people were home service technicians.
We don't know exactly how the injuries have happened.

Which of the following can be inferred from the argument above?
A. The number of people who are not home repair technicians and who have been injured while attempting home repairs has increased.
Well, hmm. We know that the total number of people injured has increased. Have the majority of injured people not been home repair technicians? Unclear? Naively, it would seem that home repair technicians might less likely to get injured, because they have some kind of training, but perhaps this training gives them the confidence to take wild risks, and so they get injured more than folks who are not home repair technicians. We don't know. We could imagine a scenario in which this is true, but we also could imagine a scenario in which this is false. This is not an inference.

B. Most people who are injured while attempting home repairs have done so while following instructions found in free do-it-yourself instructions on the Internet.
We have no way to know this. Perhaps they were following the instructions and the instructions were poorly written, or perhaps the instructions were flawless but people didn't follow them. We don't know. This is not an inference.

C. The overall sale of online do-it-yourself home repair instructions by home service technicians has not been equal to the loss of revenue the technicians have incurred due to free offerings of this sort of material.
Hmm. We didn't know about this case, home service technicians selling online do-it-yourself home repair instructions. We don't know how popular it is, how widespread, especially since there is free material on the web, but we do know quite clearly that the home service technicians have lost money: their revenue has declined. We know that. Therefore, either the sale of online instructions or any other sources of revenue must has not equaled the loss of their revenue because people do the repairs themselves. If revenue declines, loss must be greater than gain. This looks like a solid inference.

D. Most free do-it-yourself home repair instructions found on the Internet do not provide enough clear information regarding safety precautions.
Maybe--or maybe the safety information is crystal clear and people simply disregard it. We don't know. This is not an inference.

E. As more free do-it-yourself instructions for home repairs are made available on the Internet, home service technicians will suffer more losses in revenue.
This could be true, or it could be true that the market is already saturated (as often happens with free & available material). In other words, all the people who would be inclined to attempt home repairs themselves are essentially already doing so. There always will be a segment of the population--some old folks, folks who are mechanically inept, etc.--who always will opt to pay a home service technicians rather than attempt it themselves for free. If everyone besides these people are already doing it themselves, then the home service technicians' revenue has already hit bottom.

The best answer, the best inference, is (C).

It's true that (C) begins by introducing something new: home service technicians selling online do-it-yourself home repair instructions. We didn't hear about this before, but that doesn't matter. If the overall revenue has declined, any gain must be bigger than any loss.

Does all this make sense?
Mike
_________________

The correct answer choice in an inference question must be true according to the information in the text.
By presenting one case in which the selection is not true, The inference cannot be made.

Let´s have the following figures:

HST (Home Service Technicians) Revenue = 10,000
Divided in 2 parts => Repairs: 8,000 and Sales online of instructions: 2,000
Loss of revenue in repairs due to free do-it yourself instructions on the Internet = 2,000
Loss of revenue in Sales online of instructions = 0

New HST revenue = 8,000 (all loss has been in repairs)

The overall sale of online do-it-yourself home repair instructions by home service technicians is still 2,000
The loss of revenue the technicians have incurred due to free offerings of this sort of materialis 2000

So, the overall sale of online do-it-yourself home repair instructions by home service technicians has been equal to the loss of revenue the technicians have incurred due to free offerings of this sort of material, 2,000 both.

This shows that C is not always true, and thus it is not correct.
_________________

The passage says injuries caused BY people trying to attempt home repairs themselves. It seems to suggest family members were getting injured possibly.
B suggests the injuries are happening to them.
Isn't that a major reason to invalidate B?

monodeep All the passage says is that the injuries were caused by these people. There's no indication that they are injuring others, although that is certainly possible. We just don't know one way or another. I'd say the easiest way to cut B is to see the word "most" and walk away. We have no idea how these numbers compare to other sources of injury. Maybe most people who get injured while doing home repairs just happen to fall of a ladder or cut their finger, and it has nothing to do with bad instructions! Again, we just have no idea.
_________________

Yes, this is a distinction I have discussed in my comment above. Note that we don't know who is getting injured though people trying to repair are causing injuries - whether to themselves or family members etc, we don't know. Hence (B) is incorrect.

(A) The number of people who are not home repair technicians and who have been injured while attempting home repairs has increased.
We have no idea as of whether these are home repair technicians or ordinary people


(B) Most people who are injured while attempting home repairs have done so while following instructions found in free do-it-yourself instructions on the Internet.
Here too we have no idea whether thay had consulted the free to do it tutorial or took forward the task in their own risk


(C) The overall sale of online do-it-yourself home repair instructions by home service technicians has not been equal to the loss of revenue the technicians have incurred due to free offerings of this sort of material.
Yes this is a viable as there has been some looses in revenues for home repair technicians , hence let us hang onto it

(D) Most free do-it-yourself home repair instructions found on the Internet do not provide enough clear information regarding safety precautions.
Whether the the opacity in clarity is created due to non defined security precautions we don't know

(E) As more free do-it-yourself instructions for home repairs are made available on the Internet, home service technicians will suffer more losses in revenue.
We don't know whether people will switch to home repair technicians in the afterwarmth of increasing accidents

Hence IMPO C hope it helps

If you look at all the other options, A B D E all of the infer one or other part of the stimulus partially.
by PoE I chose C

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________