Inference

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Inference

by sibbineni » Sun Jan 27, 2008 12:18 pm
Recent estimates predict that between 1982 and 1995 the greatest increase in the number of people employed will be in the category of low-paying service occupations. This category, however, will not increase its share of total employment, whereas the category of high-paying service occupations will increase its share.
If the estimates above are accurate, which of the following conclusions can be drawn?

(A) In 1982 more people were working in low-paying service occupations than were working in high-paying service occupations.
(B) In 1995 more people will be working in high-paying service occupations than will be working in low-paying service occupations.
(C) Nonservice occupations will account for the same share of total employment in 1995 as in 1982.
(D) Many of the people who were working in low-paying service occupations in 1982 will be working in high-paying service occupations by 1995.
(E) The rate of growth for low-paying service occupations will be greater than the overall rate of employment growth between 1982 and 1995.

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by simplyjat » Sun Jan 27, 2008 10:42 pm
Only D makes some sense...
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by sibbineni » Mon Jan 28, 2008 3:51 am
Nope

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by simplyjat » Mon Jan 28, 2008 8:22 am
Whats the OA then...

(a) The argument talks about percentage and not the absolute number hence incorrect
(b) Again the same... number verses percentage.
(c) If we consider three fields, all of which competing for market share, and first remaining constant, second increasing, third cannot remain constant.
(e) The rate of growth will be same as the market share is not increasing...
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by simplyjat » Mon Jan 28, 2008 8:28 am
I assume that you have picked the question from one of the SETS... And the original question is mentioned here

The OA mentioned is obviously wrong, see my previous post. There is a complete difference in percentage and number, one can increase/decrease without affecting the other.

It would be really helpful in GMAT, to actually concentrate on the core concepts than just hunting questions from dubious sources. The answers are majority of times wrong and there is no explanation whatsoever for right or wrong answer! Can you actually give a reason for D being incorrect, except the OA from a dubious source...
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Re: Inference

by Stuart@KaplanGMAT » Mon Jan 28, 2008 9:02 am
sibbineni wrote:Recent estimates predict that between 1982 and 1995 the greatest increase in the number of people employed will be in the category of low-paying service occupations. This category, however, will not increase its share of total employment, whereas the category of high-paying service occupations will increase its share.
If the estimates above are accurate, which of the following conclusions can be drawn?

(A) In 1982 more people were working in low-paying service occupations than were working in high-paying service occupations.
(B) In 1995 more people will be working in high-paying service occupations than will be working in low-paying service occupations.
(C) Nonservice occupations will account for the same share of total employment in 1995 as in 1982.
(D) Many of the people who were working in low-paying service occupations in 1982 will be working in high-paying service occupations by 1995.
(E) The rate of growth for low-paying service occupations will be greater than the overall rate of employment growth between 1982 and 1995.
Inference questions ask us to draw conclusions based on a set of facts. We accept that everything in the stimulus is true and look for an answer that MUST BE TRUE based on one or more of those statements.

In this case, we know that the number of low-end employees will increase the most, while the market share of low pay employees will actually go down and the market share of high pay employees will increase. The only way that's possible is if we started off with more low pay employees than high pay.

Let's look at the 3 possible starting scenarios:

(1) equal number of both. If we had 100 of each to start and the number of low pay increased by more than the number of high pay, then the market share of low pay would be higher (relative to high pay) - impossible according to the stimulus.

(2) more high pay. If we had 100 low pay and 200 high pay and the number of low pay went up by more than the number of high pay, then the market share of low pay would be higher (relative to high pay) - impossible according to the stimulus.

(3) more low pay. If we had 200 low pay and 100 high pay and the number of low pay went up by more than the number of high pay, it would be possible that the proportion of high pay actually increases in the overall market.

Since (3) is the only possible starting scenario, it MUST be the case: choose (A).
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by sankruth » Mon Jan 28, 2008 9:14 am
I feel A is the correct answer.

Consider a case of 100 workers (80 Low-Pay, 20 High-Pay)

Since LP had the greatest increase lets say 8 new people joined, while HP had 4 new joinees

So total - 112 (88/24). As you can see 88/112 is less than 80%, although more people joined.

(A) neatly summarises this scenario.

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by simplyjat » Mon Jan 28, 2008 9:45 pm
while the market share of low pay employees will actually go down
Stuart,

Not increase is not same as decrease, not increase can also mean remain same....
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by simplyjat » Mon Jan 28, 2008 9:52 pm
sankruth wrote:I feel A is the correct answer.

Consider a case of 100 workers (80 Low-Pay, 20 High-Pay)

Since LP had the greatest increase lets say 8 new people joined, while HP had 4 new joinees

So total - 112 (88/24). As you can see 88/112 is less than 80%, although more people joined.

(A) neatly summarises this scenario.
We are assuming here that total = LP + HP which is not stated in the question. And one of the answer choices also mentions "Non Service Occupation". So it is wrong in assuming "total = LP + HP"

We can assume that "total = HPS(high-pay service) + LPS(low-pay service) + NS(non service)"
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Re: Inference

by simplyjat » Mon Jan 28, 2008 9:54 pm
Stuart Kovinsky wrote:
sibbineni wrote:Recent estimates predict that between 1982 and 1995 the greatest increase in the number of people employed will be in the category of low-paying service occupations. This category, however, will not increase its share of total employment, whereas the category of high-paying service occupations will increase its share.
If the estimates above are accurate, which of the following conclusions can be drawn?

(A) In 1982 more people were working in low-paying service occupations than were working in high-paying service occupations.
(B) In 1995 more people will be working in high-paying service occupations than will be working in low-paying service occupations.
(C) Nonservice occupations will account for the same share of total employment in 1995 as in 1982.
(D) Many of the people who were working in low-paying service occupations in 1982 will be working in high-paying service occupations by 1995.
(E) The rate of growth for low-paying service occupations will be greater than the overall rate of employment growth between 1982 and 1995.
Inference questions ask us to draw conclusions based on a set of facts. We accept that everything in the stimulus is true and look for an answer that MUST BE TRUE based on one or more of those statements.

In this case, we know that the number of low-end employees will increase the most, while the market share of low pay employees will actually go down and the market share of high pay employees will increase. The only way that's possible is if we started off with more low pay employees than high pay.

Let's look at the 3 possible starting scenarios:

(1) equal number of both. If we had 100 of each to start and the number of low pay increased by more than the number of high pay, then the market share of low pay would be higher (relative to high pay) - impossible according to the stimulus.

(2) more high pay. If we had 100 low pay and 200 high pay and the number of low pay went up by more than the number of high pay, then the market share of low pay would be higher (relative to high pay) - impossible according to the stimulus.

(3) more low pay. If we had 200 low pay and 100 high pay and the number of low pay went up by more than the number of high pay, it would be possible that the proportion of high pay actually increases in the overall market.

Since (3) is the only possible starting scenario, it MUST be the case: choose (A).
Stuart you are also making the same mistake as did by sankruth, You are not including Non-Pay services in the picture.
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by sibbineni » Tue Jan 29, 2008 4:23 pm
OA is A

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by sibbineni » Tue Jan 29, 2008 5:06 pm
OA is A

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by Stuart@KaplanGMAT » Tue Jan 29, 2008 6:42 pm
simplyjat wrote:
while the market share of low pay employees will actually go down
Stuart,

Not increase is not same as decrease, not increase can also mean remain same....
You're right, but you can replace "decrease" with "not increase" everywhere in my explanation and get the same result.

The other possible categories of pay (volunteer and medium pay) are irrelevant to the comparison between low pay and high pay.
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by sibbineni » Tue Jan 29, 2008 8:35 pm
Thanks Stuart

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by simplyjat » Tue Jan 29, 2008 8:47 pm
The other possible categories of pay (volunteer and medium pay) are irrelevant to the comparison between low pay and high pay.
however, will not increase its share of total employment
Stuart, you seem to be contradicting the argument. How are NON SERVICE jobs irrelevant in the question? Categories of EMPLOYMENT, and not Categories of PAY, are considered here...
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