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# Standard deviation comparison

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Manager
Joined: 12 Jan 2016
Posts: 144
Followers: 1

Kudos [?]: 73 [0], given: 17

Standard deviation comparison [#permalink]  31 Aug 2016, 00:07
00:00

Question Stats:

100% (00:26) correct 0% (00:00) wrong based on 3 sessions
 Quantity A Quantity B Standard Deviation of 16, 5, 14, 5, 8, 16 Standard Deviation of 6, 8, 18, 14, 18, 8

A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
[Reveal] Spoiler: OA
Intern
Joined: 09 Mar 2016
Posts: 33
Followers: 0

Kudos [?]: 15 [0], given: 11

Re: Standard deviation comparison [#permalink]  31 Aug 2016, 06:56
Can someone explain how to approach questions like this?
Intern
Joined: 17 Apr 2017
Posts: 7
Followers: 0

Kudos [?]: 7 [0], given: 2

Re: Standard deviation comparison [#permalink]  05 Sep 2017, 12:02
Director
Joined: 03 Sep 2017
Posts: 520
Followers: 1

Kudos [?]: 356 [1] , given: 66

Re: Standard deviation comparison [#permalink]  16 Sep 2017, 23:20
1
KUDOS
I don't know if this is the fastest way to do it but I've used the "informal definition" of standard deviation of Greenlight Test Prep, i.e. the standard deviation is the mean of the distance of data values from the mean. Thus, we have that column A has a mean of 32/2 = 10.67 and column B has a mean of 12. Then, computing the distance for each value from the mean I get that the approximate standard deviation of column A is equal to 4.44, while for column B it is 4.67. Thus, the answer is B!
Founder
Joined: 18 Apr 2015
Posts: 6920
Followers: 114

Kudos [?]: 1344 [2] , given: 6318

Re: Standard deviation comparison [#permalink]  18 Sep 2017, 05:42
2
KUDOS
Expert's post
Put is simple case

A. 5 8 14 16

B. 6 8 14 18

The middle terms are negligible (are the same).

A. 16-5=11

B. 18-6=12

_________________
Re: Standard deviation comparison   [#permalink] 18 Sep 2017, 05:42
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