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# Is S.D. of Set B < S.D. of Set A?

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Is S.D. of Set B < S.D. of Set A?  [#permalink]

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09 Mar 2018, 10:31
00:00

Difficulty:

25% (medium)

Question Stats:

84% (00:56) correct 16% (00:56) wrong based on 38 sessions

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Is S.D. of Set B < S.D. of Set A?
(S.D. = Standard Deviation)

1) Mean of Set A > Mean of Set B
2) Number of terms in Set A > Number of terms in Set B

Source: www.GMATinsight.com

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Is S.D. of Set B < S.D. of Set A?  [#permalink]

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09 Mar 2018, 11:06
GMATinsight wrote:
Is S.D. of Set B < S.D. of Set A?
(S.D. = Standard Deviation)

1) Mean of Set A > Mean of Set B
2) Number of terms in Set A > Number of terms in Set B

Source: http://www.GMATinsight.com

The question is asking Is the elements in Set B more closer than elements in Set A

Statement 1: if set A =(10,10,10,10,10,10,10,10,10,10) i.e. 10 elements and each element equal to 10. so mean is 10 and S.D=0

if Set B=(5,5,5,5,5), then mean =5 and S.D=0

so in this scenarios S.D of B= S.D of A. But if set A & B have different elements then S.D of B might be greater or less than S.D of A. Hence Insufficient

Statement 2: Again, we can use the same example as in Statement 1. We can get S.D either equal or greater or less than each other. Hence Insufficient

Combining 1 & 2: Clearly from above examples we cannot confirm the relationship of S.d of B & S.D of A. Hence Insufficient

Option E
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Re: Is S.D. of Set B < S.D. of Set A?  [#permalink]

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12 Mar 2018, 12:11
GMATinsight wrote:
Is S.D. of Set B < S.D. of Set A?
(S.D. = Standard Deviation)

1) Mean of Set A > Mean of Set B
2) Number of terms in Set A > Number of terms in Set B

Source: http://www.GMATinsight.com

Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

There is no relationship among the standard deviation, the average and the number of terms of data sets.
In addition, there is no way of determining the range of a set from the ranges of its subsets. Notice that “E” is in “no rElation”. Many questions about “relation” have the answer E.

A = { 100, 200 }, B = { 1 }.
SD(A) > SD(B)

A = { 99, 100, 101 }, B { 1, 99 }
SD(A) < SD(B)

Thus, E is likely to be the answer.
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Re: Is S.D. of Set B < S.D. of Set A?   [#permalink] 12 Mar 2018, 12:11
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