Q8 - Most people invest in the stock

[linda.jy.dai]

Why is the answer not D? After reading the prompt, the first and last sentence (to me) suggest that D is the correct answer.
1st sentence: "Most people invest in the stock market without doing any research of their own."
Last sentence: "Nonetheless, a majority of investors in the stock market make a profit"

In my opinion it is valid to assume (common knowledge to the general public) that a person who invests in the stock market can be labelled an 'investor.'

Can someone please point out why my reasoning is flawed? Thanks!

[ManhattanPrepLSAT1]

I love these questions...

I think the place to start is in the answer choices for this one. You seem to have a really good grasp of the important information contained in the stimulus.

The first sentence establishes that most investors don't do research.
The last sentence establishes that most investors make a profit.

From these two statements it can be inferred that at least some investors who don't do research still make a profit. This is most closely stated in answer choice (A).

Answer choice (D) says that most investors who don't do research make a profit. Let's think about this. If answer choice (D) is something that must be true, that implies that answer choice (A) is also something that must be true. There can't be two correct answers. Since answer choice (D) implies the truth of answer choice (A), but (A) does not imply the truth of (D), answer choice (A) must be the correct answer.

The simple way to put this, is that answer choice (D) is simply just a bit too strong.

[joliebella]

Can you go over why answer B is wong? Is it because of the word Some?

[ManhattanPrepLSAT1]

Let's walk through all the answer choices...

(A) can be inferred for the reasons above.
(B) is too strong. The stimulus allows us to infer that some investors would do this, but not that most would.
(C) is too specific. This answer choice combines two groups with the conjunction "while, ..." No inference can be made about investors who share both of these characteristics.
(D) is too strong. The stimulus allows us to infer that some investors would do this, but not that most would.
(E) is not necessarily true. It attempts to combine the two statements

1. Other investors often rely only on their broker.
2. Most investors in the market make a profit.

However, a MOST statement cannot be combined with a SOME statement, so no inference can be drawn!


Hope this helps with this challenging question.

[didi0504]

I picked A b/c it looked more right.....but I am having trouble seeing why B is wrong

can you explain B?

thanks!

[b91302310]

The argument says that, among most of people who invest without doing research, some solely rely on brokers, and some others solely rely on hunches. Since "some others" refers to some of the people who do not make decision based on broker's advice, could there be people,who make investment without doing research,rely on sources other than broker's advice or hunches ?


Could anyone help to explain?
Thanks!

[ManhattanPrepLSAT1]

could there be people,who make investment without doing research,rely on sources other than broker's advice or hunches ?

Sure. There could be. But there doesn't have to be and for this question, the correct answer must be something we can prove must be true.

The overlaps over the groups involving "some" statements just can't be determined strong enough to guarantee anything.

I like how you were careful on the language "some others." It shows a strong attention to detail. Know when to rely on it, and when to let your instincts take over and do most of the work. That will help you go faster. This is one that is a bit trickier with so many claims to keep track of, so it's good you were careful.

[romanmuffin]

Let's walk through all the answer choices...

(A) can be inferred for the reasons above.
(B) is too strong. The stimulus allows us to infer that some investors would do this, but not that most would.
(C) is too specific. This answer choice combines two groups with the conjunction "while, ..." No inference can be made about investors who share both of these characteristics.
(D) is too strong. The stimulus allows us to infer that some investors would do this, but not that most would.
(E) is not necessarily true. It attempts to combine the two statements

1. Other investors often rely only on their broker.
2. Most investors in the market make a profit.

However, a MOST statement cannot be combined with a SOME statement, so no inference can be drawn!


Hope this helps with this challenging question.

Question about answer choice C. Isn't the group which "does some research on their own, but just as often relies only on their broker or on hunches" addressed in the stimulus? The answer choice does not create this group. It is already addressed in the stimulus! Can you explain this a bit further? Thanks!

[ManhattanPrepLSAT1]

Sure! The group is not created in the answer choice, but there is no inference that can be made about this group. According to the stimulus there are some investors who conduct research on their own, but just as often rely only on their broker or on hunches, but we cannot say that they make a profit...

Make sense?

[geverett]

Hey Matt,
I got to this answer choice by process of elimination. However, the first sentence seems to speak about "people in general." Whereas the last sentence seems to speak about a subgroup - "people who are also investors."

Thoughts?

[ManhattanPrepLSAT1]

Both statements are about investors. The first statement can be interpreted as "most investors don't do any research" whereas the last statement can be interpreted as "most investors make a profit."

I can see why you feel the first statement is more general, but it's just semantics, they're both talking about the frequency with which investors do certain things.

Make sense?

[geverett]

Hey Matt,
Kind of. I feel like if the first sentence was talking about the subgroup of "investors" then it would say something more like:

Most people who invest in the stock market do so without doing any research of their own.

Still seems like it could be interpreted to be people in general.

[ManhattanPrepLSAT1]

Try putting numbers on it to see if you could make it so the statement, "most people both invest in the stock market and do not do any research," would permit it to be the case that half or more investors do research.

If you could make that work, I think you'd have a challenge to the answer choice. Let me know what you come up with!

[eunjung.shin]

Sure! The group is not created in the answer choice, but there is no inference that can be made about this group. According to the stimulus there are some investors who conduct research on their own, but just as often rely only on their broker or on hunches, but we cannot say that they make a profit...

Make sense?

No inference can be made because it says "other people" rather than "other investors"?
Unless they are a different group, i think an inference can be made to make C correct. What do you think?

[lorraineogan]

I love these questions...

Answer choice (D) says that most investors who don't do research make a profit. Let's think about this. If answer choice (D) is something that must be true, that implies that answer choice (A) is also something that must be true. There can't be two correct answers. Since answer choice (D) implies the truth of answer choice (A), but (A) does not imply the truth of (D), answer choice (A) must be the correct answer.

The simple way to put this, is that answer choice (D) is simply just a bit too strong.

But is D is still technically correct? That is, suppose A's content were not an option, and had some crazy silly answer instead. Would the next best choice be D, then?

[kumsayuya]

Okay, I’ll take a shot at explaining this one.

A. I think this one’s easier to see if we break it down into groups of investors:

• People who do no research of their own
• People who rely on brokers advice (while doing no research of their own)
• People who make decisions on hunches (no research of their own)
• Some DO do the research on their own – but just as often will not do research of their own
• Only a few (small group) will do research on their own.

So as we can see basically the first four groups are composed of people who do not want to do any research before they invest, and only the last group is one the always does their research before they are chosen – and they even tell us this group is very small (only a few!). So we know that for the most part, people who do not do their own research make up the investors, and therefore, must make up at least some of the group that makes a profit from investing.

B. We only know that some people rely on their broker, and some make decisions on hunches. Some could technically mean only 1. So therefore, saying MOST people who rely on hunches or brokers is actually way too strong – most meaning 50 percent or greater – we only know SOME people do this, which could include most.. but it also could not – and this is a must be true, so we must eliminate this answer choice.

C. I think that it could be true that some people who do investment research on their own, while also relying on hunches, make NO profit at all from the stock market. The stimulus says that majority of investors in the stock market make a profit, but there is nowhere that states these particular groups necessarily make ANY profit at all, we just know that majority makes a profit.. but what comprises this majority? We don’t know..

D. This one is a bit tricky. So, we know that most people invest in the stock market without doing any research on their own. Does this mean that they make a profit though? Nope. We don’t know if they make a profit, and that is exactly what is stated at the end of this answer choice, that they make a profit. Investing =/= a profit.

E. Its comparing this hunch group to the broker group. In reality, we don’t know much about these groups, and we know nothing about their relative success to each other as a group. So saying that one group is more successful than another for a must be true is incorrect

[jenniferreisig]

All of the answer choices gave us inference options of "some" and "most". I eliminated B, D & E right away because we can't make any inference that most anyone does anything. There are no absolutes mentioned (all or none) so we need to rely on "most" to make any inferences - and at best two mosts could be inferred to as "some", A & C. The conclusion of the stimulus is that a majority (or most) of the people make a profit. The only other "most" mentioned in the stimulus were those who invest without doing any research. Therefore, the only inference you can get from any of this is that some people make a profit do so without any research - A.

[contropositive]

All of the answer choices gave us inference options of "some" and "most". I eliminated B, D & E right away because we can't make any inference that most anyone does anything. There are no absolutes mentioned (all or none) so we need to rely on "most" to make any inferences - and at best two mosts could be inferred to as "some", A & C. The conclusion of the stimulus is that a majority (or most) of the people make a profit. The only other "most" mentioned in the stimulus were those who invest without doing any research. Therefore, the only inference you can get from any of this is that some people make a profit do so without any research - A.

Those were my thoughts too when I eliminated B, D, and E. I have learned about this technique in my prep-company but sometimes it gets confusing. We can eliminate B, D, and E because the argument contained quantifiers such as "some" and "most" ; not strong quantifiers such as "all" or "none" , right? you mentioned there is only "most" statements but there was also "some" statements. By the way, does this approach work on all question types? thats what I have been told but I am always afraid of messing up if I apply it. It was easier to apply it for this argument since it relied heavily on quantifiers.


Also, can someone further elaborate on answer choice C? I read the above explanations on it but I'm still confused. Its been said that we cannot make an inference about the people who do some research of their own, yet rely only on broker advice or hunches. If we cannot make inference about those people then how can we make inference about those who do research on their own?

During review I thought maybe another problem with C could be that it's talking about "investment research" whereas the argument does not specify what type of research. I doubt this is the problem because it just seems like common sense to assume the argument is talking about investment research and it is way early in the section to be picky about details.

Also, the reason why I did not like A is because it looks like an incorrect negation. Although I did not use logical chain (dislike them), the answer choice started off with people who make a profit. However, the argument's conclusion (necessary) is about people who make a profit so the answer choice is placing the necessary into the sufficient spot?

[maryadkins]

Nice discussion of (B) (D) and (E).

(C) doesn't have to be complicated to eliminate. You can do it for the same reason you eliminated those others.

Basically it's this:

Some + Most = DOES NOT INDICATE NECESSARY OVERLAP

All we know from the stimulus is that some people do research on their own, and that most investors make a profit. Do these necessarily overlap, as (C) suggests? No, because some plus most does not give us any inference on the LSAT.

In this question, only most + most indicates an overlap (of "some"), which is answer choice (A).

If this remains difficult please review Chapter 8 of the MPrep LR Strategy Guide.

[QingyiY938]

I also initially chose C and was between C and A. But there can't be two correct answers so I thought what's the difference?

The stimulus tells us there are four groups of people. no research (most - more than half), (some)only hunches,(some) only brokers, and (some)own research and broker/hunch. Then we come to the conclusion that most people still make a profit.

From this, we know that if you made a profit (in this big group of people who use different strategies), one of them has to be someone who didn't do research. The most most overlap gives us this (if most ppl do no research and most people make a profit, there has to be one who does both) This is what A illustrates.

However, C is the opposite, it takes one group and says some people in the last group (research plus hunch/broker) make a profit. Sure, maybe, but we don't know. Maybe the "majority" of profit winners only encompass the first three groups of people. We don't have a guaranteed overlap in groups.

D and E commit the same mistake. We don't know how many of them are in this winning pool. I think if you visualize by drawing a circle and slicing the groups, it helps to see that the winning part doesn't have to over lap any group except the no research group (because all the other groups are too small (some can be 1 person).

B is wrong because we don't know the exact number of people involved in each group. even if it said more people are int he no research group than hunch group, we can be pretty sure but not 100% sure. Because most guarentees us more than 50 percent, but some doesn't mean less than 50 percent. just more than 0 percent.