Q16 - The advanced technology of ski

[b91302310]

I am stuck in (B) because it can also be right by referring to the last sentence. So, could anyone explain why (B) is wrong?

Thanks.

[bbirdwell]

The last sentence simply says that the incidence of non-slope injuries increases as the amount of alcohol per skier increases.

This does not say that the amount of alcohol consumed did in fact increase, as (B) says, it simply says that these injuries are more likely to occur when more alcohol is consumed.

To get this question right, you must pay careful attention to which total the percentages refer.

In order for the percentage of non-slope injuries out of total injuries to increase, no change in the frequency of those injuries is necessary. As the text says, that particular % will increase simply as a result of the % of other injuries decreases.

Here's the same example with smaller numbers:
Let's say that in 1999, 8 of every 20 skiers were injured on the slopes. In 2005, only 2 of every 20 skiers were injured on the slopes.

Now, of all ski-related injuries, 2 in 1999 were non-slope related, and in 2005, 2 were non-slope related. The same number of non-slope injuries has occurred. However, the % has increased. In 1999, 2 of 10 total injuries were non-slope (20%), and in 2005, 2 of 4 were (50%).

See what I mean?

[rpcuhk]

The last sentence simply says that the incidence of non-slope injuries increases as the amount of alcohol per skier increases.

This does not say that the amount of alcohol consumed did in fact increase, as (B) says, it simply says that these injuries are more likely to occur when more alcohol is consumed.

The last sentence unequivocally says that these injures increase when more alcohol is consumed. I don't see where you get notion that it only says the injuries are more likely to occur.

[goriano]

The last sentence simply says that the incidence of non-slope injuries increases as the amount of alcohol per skier increases.

This does not say that the amount of alcohol consumed did in fact increase, as (B) says, it simply says that these injuries are more likely to occur when more alcohol is consumed.

The last sentence unequivocally says that these injures increase when more alcohol is consumed. I don't see where you get notion that it only says the injuries are more likely to occur.

The last line says "the incidence of THESE injuries (meaning non-slope related injuries) increases WITH the amount of alcohol consumed per skier." Note that it does not say WHEN the incidence of these injuries increases, the amount of alcohol consumed per skier increases. If the last line had said this, I *think* we would be able to conclude (B).

So since the last line only states that there is a correlation between the incidence of non-slope injuries (X) and amount of alcohol consumed per skier (Y), the possibilities are:

X --> Y
Y --> X
Z --> X and Y

From the stimulus we know that X occurred, but based on the three possibilities above, in only one of them are we certain to know that Y occurred as well.

I'd love to get feedback from the geeks on this explanation, because I struggled with this question!

[timmydoeslsat]

The last line says "the incidence of THESE injuries (meaning non-slope related injuries) increases WITH the amount of alcohol consumed per skier." Note that it does not say WHEN the incidence of these injuries increases, the amount of alcohol consumed per skier increases. If the last line had said this, I *think* we would be able to conclude (B).

So since the last line only states that there is a correlation between the incidence of non-slope injuries (X) and amount of alcohol consumed per skier (Y), the possibilities are:

X --> Y
Y --> X
Z --> X and Y

From the stimulus we know that X occurred, but based on the three possibilities above, in only one of them are we certain to know that Y occurred as well.

I'd love to get feedback from the geeks on this explanation, because I struggled with this question!

I think you have figured out that the alcohol reference in the stimulus is not even applicable to anything we can infer.

As you stated, we are given information that says:

Amt. alcohol per skier increases incidence of non-slope ski injuries

To have the issue of alcohol even be applicable to this stimulus we would need this kind of language:

% of non-slope ski injuries increases with the amount of alcohol per skier.

Answer choices:

A) Is not inferrable. A decrease in the % of slope injuries will necessarily lead to an increase of % non-slope injuries in terms of the % of all ski injuries. So we do not have to have more injuries on the non-slope side. It could stay the same or even drop, just not by as much as the slope side.

B) Could be true, not necessarily true. This can be thought of as reversed logic. We know that alcohol could lead to the increase. And we do have an increase. Does not mean alcohol was the cause.

C) Each type of ski injury? We know it is affecting ski injuries, but not every type.

D) Temporal flaw. We cannot infer anything about the future.

E) Wins by default. However, it can still be proved.

We know that the % of slope injuries in 1950 was 90% while in 1980 it was 75%.


And goriano, while it may be true that a correlation was cited between alcohol and incidence of non-slope injuries, this does not rule out that we could infer that more injuries happened. We are just not given the information in a manner in which we can infer that.

So this stimulus could have given us that ability to infer. We would have been able to conclude that alcohol did increase, however that would not be stating cause. It would be stating a fact, however.

[seychelles1718]

For A, are we comparing the number of on-slope injuries s vs the number of non-slope injuries, or, the number of on-slope injuries vs the number of ALL ski-related injuries? I thought A is talking about the latter but after reading the explanation by timm, I am confused..

I eliminated A because I thought it was simply comparing the wrong things together - i.e. the number of on-slope injuries vs the number of ALL ski related injuries (including on-slope injuries), from which we can't really infer anything based on the stimulus.

If A was comparing the number of on-slope injuries vs the number of non-slope injuries, would A be true?

[ohthatpatrick]

I think your interpretation seems correct --
"# of slope injuries" is a subset of "# of ski resort injuries".

You're saying, what if they were defined mutually exclusively --
"as slope injuries go down, non-slope injuries go up"

That would still be incorrect. They never gave us that sort of connection.

Imagine a room with 2 women, 3 men.
It's 40% women and 60% men.

A woman walks out and now it's 1 woman, 3 men.
It's 25% women and 75% men.

Women = "slope injuries"
Men = "non-slope injuries"

As the number of women decreased, the PERCENTAGE of men went up (just as non-slope went from 10% to 25%), but the NUMBER didn't increase.

[JoP960]

The last sentence simply says that the incidence of non-slope injuries increases as the amount of alcohol per skier increases.

This does not say that the amount of alcohol consumed did in fact increase, as (B) says, it simply says that these injuries are more likely to occur when more alcohol is consumed.

The last sentence unequivocally says that these injures increase when more alcohol is consumed. I don't see where you get notion that it only says the injuries are more likely to occur.

I think you are right.