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The chart above represents the number of students at five schools, eac

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Bunuel
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The chart above represents the number of students at five schools, eac [#permalink] New post   12 Jan 2017, 00:12
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The chart above represents the number of students at five schools, each of which has branches in each of four towns. In which town is the standard deviation of the number of students at each school the greatest?

A. Town A
B. Town B
C. Town C
D. Town D
E. It cannot be determined from the information given.
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D
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Re: The chart above represents the number of students at five schools, eac [#permalink] New post   12 Jan 2017, 07:01
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Bunuel wrote:

The chart above represents the number of students at five schools, each of which has branches in each of four towns. In which town is the standard deviation of the number of students at each school the greatest?

A. Town A
B. Town B
C. Town C
D. Town D
E. It cannot be determined from the information given.


To understand the solution, we should first understand the theory of Standard Deviation.

Standard Deviation in lay man's language means deviation from the mean i.e. A sample in which numbers are close to each other would have low Standard deviation in comparison to the sample in which numbers are not close.

In above Question if you look at town C, number of students in each school doesn't vary much in comparison to the number of students in either of Town A, B or D.
So, C is not the answer. Easy Choice..

Now if we compare Town A & B - Numbers are close to mean in Town B in comparison to town A's.
So we can discard option B as well.

Now if we compare Town A & D - Numbers are close to mean in Town A in comparison to town D's.
So we can discard option A as well.

Thus Answer D
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The chart above represents the number of students at five schools, eac [#permalink] New post   21 May 2017, 02:49
Bunuel - is there a method to select the right option out of A,B and D without doing calculations?
Because I am unable to figure out the maximum deviation from mean amongst A,B and D just by looking at the table.

Please guide
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Re: The chart above represents the number of students at five schools, eac [#permalink] New post   21 May 2017, 04:55
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Bunuel wrote:

The chart above represents the number of students at five schools, each of which has branches in each of four towns. In which town is the standard deviation of the number of students at each school the greatest?

A. Town A
B. Town B
C. Town C
D. Town D
E. It cannot be determined from the information given.


Standard Deviation is Maximum when the terms in the set are widely separated.

If we look at the distances among schools townwise then we can infer that Town D has most widely separated schools hence Town D has maximum Standard deviation


Likewise we can say that the smallest deviation will be available in town C

Answer: option D
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Re: The chart above represents the number of students at five schools, eac [#permalink] New post   07 Sep 2019, 20:14
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Re: The chart above represents the number of students at five schools, eac [#permalink]
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