Are these valid arguments, and how do I properly diagram them? (Please help)

LSAT Determined

1. People with long legs make good runners. Everyone in Ashley's family has long legs. Therefore, Ashley would make a good runner. (I think it's a bad argument because just because Ashley's family has long legs doesn't necessarily mean she does, right?)

2.In Los Angeles everyone over the age of 18 who drinks also smoke. But not everyone in Los Angeles over the age of 18 who smokes are drinks. It follows tear among people over the age of 18 in Los Angeles there are more who drink than there are who smoke. (this felt like a bad argument to me)

3. All of the painting in the Janet Collection will be put up for auction next week. Since the paintings to be auctioned next week are by a wide variety if artists, it follows that the paintings in the Janet collection are by a wide variety of artists (This felt like a bad argument to me)

4. A writer's first book will become a best-seller only if it has a romantic setting and a suspenseful plot. Since many author's first novels have neither, it follows that not many first novels become best-sellers. (I thought this was a good argument)

5. Some short poems are thematically pluralistic, since some sonnets are characterized by such pluralistic, and all sonnets are short poems. (I thought this was a bad argument, because I couldn't diagram it)

6. Most of the people in Los Angeles buys gasoline on Mondays only. But almost everyone in Los Angeles buys groceries on Tuesday only. It follows that fewer than half of the people in Los Angeles buy gasoline on the same day on which they buy groceries.

c.janson35

EDIT: it is clear that these are not official LSAT questions. Just a testament to how precise and clear LSAC is, because I knew immediately that these were not.

1.
LL-->MGR
IAF-->LL
------------------
IAF-->MGR

Good argument, because Ashley is in her family, which means she has LL and would there MGR.

2.
If Drink--->Smoke, (so there are at least as many drinkers as smokers; there's no way for there to be more drinkers than smokers here, because anyone who is a drinker is also a smoker. For argument's sake, let's say these groups are equal).

Smoke some /Drink, (which means there's at least one more smoker than drinker.)

So we have equal in the first group, +1 smoker in the second, which means there are more who smoke than drink. This is not what the conclusion says.

3. This seems to be committing a whole to part flaw, because it is concluding that the particular collection of paintings must be by a wide satiety just because all of the paintings on sale are by a wide variety.

4. This one is tricky. We only know what must be true for a writers' first book to be a best seller, and so this does not apply to any books after an author's first. With that said, we would have to assume that the first novel a writer wrote is necessarily his or her first book in order to properly draw the conclusion, which I don't think is a safe assumption to make. What if all novelists have previously tried to write a nonfiction book? Then it would not matter whether their novel had a RS or SP in order to be a best selling book, because those conditions would only be necessary for the novelists' first nonfiction book to be a best seller, not their second book even though it is their first novel. The sufficient condition is not about an author's first book of a certain type, but a first book in general. I would say this is a bad argument.

5. S-->SP
TP some S
-----------------
SP some TP

Good argument.

6. PLA most BGMO
PLA most BGrTO

The proper conclusion you can draw here is: Some people in Los Angeles who buy gasoline on Monday only also buy groceries on Tuesday only. Which means that some people are buying their groceries on different days, but this is different than saying only some people are buying on the same day. Bad argument.

brna0714

Just curious- where are you getting these?