Q21 - Most large nurseries sell raspberry

[giladedelman]

Thanks for posting!

I think we can find support for (E), actually. See, we know that most large nurseries sell only plants that are guaranteed to be disease-free. But Wally received a shipment of diseased plants. If he bought it from a large nursery, it was probably guaranteed to be disease-free. But since the shipment is actually diseased, it couldn't be entirely in keeping with that guarantee. Does that make sense?

(A) is unsupported because if the shipper isn't a large nursery, then we have no idea whether it's guaranteed to be disease-free.

(B) is out because there's no support for the idea that if you get a lousy batch of plants, you're not a commercial grower.

(C) is really tempting, but we just know that large nurseries sell "primarily" to commercial growers. That still leaves them free to also sell to non-commercial growers. So the fact that Johnson is not a commercial grower wouldn't be enough for us to say that Wally's is probably not a large nursery.

(D) brings in "well-run," which is totally out of scope. Also we have no way to say it's probably not a large nursery, it just seems that if they are, they made a false guarantee.

Does that clear this one up for you? Tricky.


#officialexplanation

[catie0128]

I had trouble with this one. It seems as if all the answer choices don't match up to the stimulus.

[zainrizvi]

Thanks for posting!

I think we can find support for (E), actually. See, we know that most large nurseries sell only plants that are guaranteed to be disease-free. But Wally received a shipment of diseased plants. If he bought it from a large nursery, it was probably guaranteed to be disease-free. But since the shipment is actually diseased, it couldn't be entirely in keeping with that guarantee. Does that make sense?

(A) is unsupported because if the shipper isn't a large nursery, then we have no idea whether it's guaranteed to be disease-free.

(B) is out because there's no support for the idea that if you get a lousy batch of plants, you're not a commercial grower.

(C) is really tempting, but we just know that large nurseries sell "primarily" to commercial growers. That still leaves them free to also sell to non-commercial growers. So the fact that Johnson is not a commercial grower wouldn't be enough for us to say that Wally's is probably not a large nursery.

(D) brings in "well-run," which is totally out of scope. Also we have no way to say it's probably not a large nursery, it just seems that if they are, they made a false guarantee.

Does that clear this one up for you? Tricky.

I understand that "well-run" is out of scope in choice (D) but why can't we evoke the contrapositive to say thats it probably not a large-well run nursery?

Is it because it says GUARANTEED to be disease-free?

If the stimulus said, "most large nurseries sell raspberry plants primarily to commercial raspberry growers and sell only plants that ARE disease-free". Then we could invoke contrapositive, NOT only plants that are disease free -> ... wait

You can't evoke the contrapositive with "most" ...

That's the primary reason (D) is wrong. (E) doesn't really need contrapositive to function.

[noah]

I understand that "well-run" is out of scope in choice (D) but why can't we evoke the contrapositive to say thats it probably not a large-well run nursery?

I appreciate the drive to pick this one apart, but I think you're reading into the stimulus. There's no mention of anything be well run or not.

And, it's true you can't evoke the contrapositive of "most" statements, but the reason (D) is wrong is really what Gilad said.

[drb_]

Since "most" statements don't have contrapositives, is it correct to eliminate the answer choices if it concerns Wally NOT being a large nursery and Johnson NOT being a commercial grower (which is negating a most statement)? The only definitive statement is selling guaranteed disease-free plants.

So, we can only assume what would happen if Wally IS a large nursery and if Johnson IS a commercial grower? Or does "most" and "primarily" leave it undefined?

This question left me confused.

Additionally, if diagramming this, would I diagram it as two separate statements or one?

Most large nurseries -> primarily sell to commercial growers + only sell disease-free plants

OR

Most large nurseries -> primarily sell to commercial growers
Most large nurseries -> only sell disease-free plants

Any input would be appreciated.

[coco.wu1993]

Since "most" statements don't have contrapositives, is it correct to eliminate the answer choices if it concerns Wally NOT being a large nursery and Johnson NOT being a commercial grower (which is negating a most statement)? The only definitive statement is selling guaranteed disease-free plants.

So, we can only assume what would happen if Wally IS a large nursery and if Johnson IS a commercial grower? Or does "most" and "primarily" leave it undefined?

This question left me confused.

Additionally, if diagramming this, would I diagram it as two separate statements or one?

Most large nurseries -> primarily sell to commercial growers + only sell disease-free plants

OR

Most large nurseries -> primarily sell to commercial growers
Most large nurseries -> only sell disease-free plants

Any input would be appreciated.

I'd like to know this as well. Do "most" statements have contrapositives? Is this a partial reason why C is wrong? Thanks in advance!

[ohthatpatrick]

Most statements do not have contrapositives, since they aren't conditional.

However, you can use a most statement like a conditional to prove LIKELIHOOD, not certainty:

Given:
Most Senators are Male.
Leslie is a Senator.

you can correctly infer:
Leslie is probably male.

So if you REALLY wanted to (and you probably shouldn't want to), you could think of that most statement as
Senator --> probably male

But to write a contrapositive of that would distort everything.

IF you're NOT probably male, then you're not a Senator??!

=====
Most men are right handed.

Does that mean that if you're left handed, you're probably not a male?

No it doesn't. Most females are right handed too. Given only those facts, there's no way to know whether a left handed person is more likely to be male or female.

======

Someone asked should the original be diagrammed as

Large nurs --> primarily to commercial AND guar. disease free
or
Large nurs --> primary to commercial
Large nurs --> guar. disease free

Those are identical ways of dealing with a conditional. You can always split up an AND in the necessary.

X --> Y and Z
gives you
X --> Y
and
X --> Z

So it's up to your preference. I think in this problem it's easy to confuse yourself into thinking

Large nursery --> selling guaranteed disease free plants to commercial growers

That would be a distortion. So it might be more clear to think of the first sentence as telling us two distinct facts about most large nurseries.

Most LN's = sell primarily to commercial growers
Most LN's = guarantee their plants are disease free

(again, I was using conditionals because that's what the poster asked about, but "most" is NOT conditional).

=====

Another poster asked, "is it an immediate dealbreaker if we see an answer saying 'If NOT commercial' or 'If NOT large nursery'?"

I think you're right. The information provided doesn't let us assume anything about how smaller nurseries conduct business or about how non-commercial growers do so.

Seen through that lens:

(A) I can't predict anything about what would be true if Wally's is NOT a large nursery

(B) There's no way to prove J is PROBABLY not a commercial grower because there was no fact provided about MOST commercial growers.

(C) I don't know anything about non-commercial growers.

(D) I could potentially say PROBABLY not large nursery, because there was a fact about MOST large nurseries. But I can't say anything about well-run nursery because that term/idea wasn't discussed.

Hope this helps.

[graftedinspiration]

I think the book mentiont inverse links from most to some.

Ex. Most sentators are male.

Thus, at least some non-males are Senators, right?

What I wonder is if it's safe to always try to reason in the same "direction" as the prompt, as is the case here. It seems many of us tried to reason in the "opposite direction" and screwed up.

Nevertheless, I remember the Manhattan book going to great lengths to explain opposite direction resoning, as above. The crux comes down to the fact that "some" is not "probable."

Answer to !? above appreciated...

[ohthatpatrick]

'Most senators are male' does NOT allow you to infer that 'some senators are not-male'.

It's POSSIBLE that some senators are not-male, but it's not provable from the 'most' claim.

Consider these. Are they true or false?

- Most NFL players are men
- Most US Presidents have been men

They're both true.

Yet we know that there are NO female NFL players and there have (sadly) been NO female US Presidents.

'Most' just means more than 50%.

100% is more than 50%.

Naturally, in everyday usage, quantity terms insinuate certain things they don't technically mean.

In real life, if I say
"Most of my friends are Democrats", then you fairly assume that some of my friends AREN'T Dems.

On LSAT,
more than 50%, and possibly all, of my friends are Dems.

In real life, if I say
"Some of my friends are Republicans", you assume that they're probably in the minority.

On LSAT,
you know AT LEAST ONE, and possibly all, of my friends are Republicans.

(Remember, it's a true statement to say "Some NFL players are men")

In real life, if I say "Not all my friends are Democrats", you assume that I'm a raging liberal with mostly Democratic friends but a few token non-Democrat friends.

On LSAT,
you know AT LEAST ONE, and possibly ALL, of my friends are not Democrats.

(Remember, it's a true statement to say "Not all NFL players are female")

As for your "should we ALWAYS go in the direction of the argument" question, I'm not sure what you mean.

However, I would automatically caution you against assuming there's anything such as a "I should ALWAYS do ____" rule for LSAT.

There are tons of variations, since they want us to think flexibly (on harder questions).

If by "going the opposite direction", you're referring to using the contrapositive, you DEFINITELY will see tons of correct answer choices go that direction.

This question is the essence of what LR sections get like in problems 14-22 or so .... they avoid reliable patterns and supply correct answers you wouldn't have seen coming (or present them in unusual linguistic forms you'll have to decode on the fly).

Hope this helps.

[513852276]

"Most Senators are Male.
Leslie is a Senator.

you can correctly infer:
Leslie is probably male."

I think "Leslie is probably male" is false, as individual characteristics may inconsistent with group characteristics. We have no clues whether Leslie is a representative senator in gender tendency.

If he is not, we couldn't write conditional statement like "Senator--> probably male" at first place.

The correct condition statement is:

Most senators--> Male.
(If your gender group is shared by most of Senators in gender, then you are a male. )

Contrapositive: Not male--> not most senator.

N.B. "Not most senator" means your gender group is not shared by most of senator. It tells nothing about whether you yourself are a senator or not. Hence, statement like "probably not a senator" and "not probably a senator" are all false.

While I thought the expression "Most senators=male" a little bit misleading, as we also use "=" to denote "if and only if" condition, which is not the case in this stimulus.

If indeed, Leslie is representative of gender characteristics for senator group, and we write:

Senator---> probably male.

Then contrapositive "not probably male---> not senator" also hold. If one person which is representative for group gender characteristics do not likely (>50%) to be male, then we concludes he/she is not randomly selected from a senators' group.

-----
Hence, correct answers in C could say "if J is not a commercial raspberry grower, then WP is different from the most of large nurseries in its' choice of growers. "

[ohthatpatrick]

I definitely appreciate your attention to detail, but I don't want to get even MORE technical with this thread, when the whole thrust of our advice was to simplify our way of thinking on this problem.

When I wrote
"Most LN's = sell primarily to commercial growers
Most LN's = guarantee their plants are disease free"

I definitely was not talking about bi-conditional ideas. Sorry to give that impression. The sentence after that one was reiterating that I am NOT treating "most" conditionally.

In my Leslie/Senator example, yes, we're assuming representativeness.

Senators are like marbles in a jar, or cards in a deck ... we're saying on an even playing field, an equal likelihood of random sampling, you can make probabilistic assertions based on knowledge of a majority.

Your alternative version of (C) did sound correct to me.

(Although one thing I just noticed about the stimulus is that it says most growers sell PRIMARILY to commercial growers. It seems like you can interpret that claim to mean "More of their clients are commercial than noncommercial" OR to mean "More of their business (revenue) comes from commercial than noncommercial clients". I don't see how they've forced the former interpretation, and without that it's hard to make any numerical inferences the likelihood of being either type of grower.)