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# Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added

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Intern
Joined: 23 Jun 2018
Posts: 31
Location: India
WE: Sales (Mutual Funds and Brokerage)
Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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11 Nov 2018, 23:37
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55% (hard)

Question Stats:

40% (01:15) correct 60% (01:34) wrong based on 67 sessions

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Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added in the list, what will be the value of X so that the standard deviation (S.D.) of the final list of 6 terms is minimum?

A - 20
B - 15
C - 30
D - 10
E - 0

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Krunali Gokani
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9326
Location: Pune, India
Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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11 Nov 2018, 23:45
3
1
KrunaliG wrote:
Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added in the list, what will be the view of X so that the standard deviation (S.D.) of the final list of 6 terms is minimum?

A - 20
B - 15
C - 30
D - 10
E - 0

Posted from my mobile device

SD is minimised by having maximum terms at the mean.
The mean of 5,10,15,20, 25 is 15.

So the new number should be 15 too so that the SD does not increase but in fact decreases to get the minimum SD.

Note: When you post a question, please ensure that you write it verbatim. Also, use the standard format of putting down options (A) (B) etc. A - makes one think that the numbers are negative.

For more on SD, check: https://www.veritasprep.com/blog/2012/0 ... deviation/
_________________
Karishma
Veritas Prep GMAT Instructor

Intern
Joined: 23 Jun 2018
Posts: 31
Location: India
WE: Sales (Mutual Funds and Brokerage)
Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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11 Nov 2018, 23:48
KrunaliG wrote:
Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added in the list, what will be the view of X so that the standard deviation (S.D.) of the final list of 6 terms is minimum?

A - 20
B - 15
C - 30
D - 10
E - 0

Posted from my mobile device

SD is minimised by having maximum terms at the mean.
The mean of 5,10,15,20, 25 is 15.

So the new number should be 15 too so that the SD does not increase but in fact decreases to get the minimum SD.

Note: When you post a question, please ensure that you write it verbatim. Also, use the standard format of putting down options (A) (B) etc. A - makes one think that the numbers are negative.

Thank you so much for such a brief solution!
And yes will take care of the note too, thank you for the guidance.
_________________
If you liked my post, kindly give me a Kudos. Thanks.
Krunali Gokani
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9326
Location: Pune, India
Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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12 Nov 2018, 00:20
KrunaliG wrote:
KrunaliG wrote:
Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added in the list, what will be the view of X so that the standard deviation (S.D.) of the final list of 6 terms is minimum?

A - 20
B - 15
C - 30
D - 10
E - 0

Posted from my mobile device

SD is minimised by having maximum terms at the mean.
The mean of 5,10,15,20, 25 is 15.

So the new number should be 15 too so that the SD does not increase but in fact decreases to get the minimum SD.

Note: When you post a question, please ensure that you write it verbatim. Also, use the standard format of putting down options (A) (B) etc. A - makes one think that the numbers are negative.

Thank you so much for such a brief solution!
And yes will take care of the note too, thank you for the guidance.

Sure! Check out the link I have provided. You will find it useful.
_________________
Karishma
Veritas Prep GMAT Instructor

Director
Joined: 27 May 2012
Posts: 800
Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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09 Jan 2019, 04:30
1
KrunaliG wrote:
Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added in the list, what will be the view of X so that the standard deviation (S.D.) of the final list of 6 terms is minimum?

A - 20
B - 15
C - 30
D - 10
E - 0

Dear Moderator,
Just came across this question, the term "view" confused me a lot , then I realized it was meant to be " Value ", seems this is a typo. Hope you will look into this and do the needful. Thank you.
_________________
- Stne
Math Expert
Joined: 02 Sep 2009
Posts: 55629
Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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09 Jan 2019, 04:35
stne wrote:
KrunaliG wrote:
Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added in the list, what will be the view of X so that the standard deviation (S.D.) of the final list of 6 terms is minimum?

A - 20
B - 15
C - 30
D - 10
E - 0

Dear Moderator,
Just came across this question, the term "view" confused me a lot , then I realized it was meant to be " Value ", seems this is a typo. Hope you will look into this and do the needful. Thank you.

___________________
Edited. Thank you.
_________________
Manager
Joined: 28 Mar 2017
Posts: 57
Location: Sweden
Concentration: Finance, Statistics
Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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09 Jan 2019, 05:21
Please remove the - sign on the answer choices! They look like a negative sign

Posted from my mobile device
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Intern
Joined: 08 Dec 2018
Posts: 9
Location: India
Schools: ISB '20
Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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16 Mar 2019, 08:21
Bunuel wrote:
stne wrote:
KrunaliG wrote:
Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added in the list, what will be the view of X so that the standard deviation (S.D.) of the final list of 6 terms is minimum?

A - 20
B - 15
C - 30
D - 10
E - 0

Dear Moderator,
Just came across this question, the term "view" confused me a lot , then I realized it was meant to be " Value ", seems this is a typo. Hope you will look into this and do the needful. Thank you.

___________________
Edited. Thank you.

Why Option D is wrong ?
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9326
Location: Pune, India
Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added  [#permalink]

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22 Mar 2019, 05:59
KrunaliG wrote:
Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added in the list, what will be the view of X so that the standard deviation (S.D.) of the final list of 6 terms is minimum?

A - 20
B - 15
C - 30
D - 10
E - 0

Posted from my mobile device

SD is minimised by having maximum terms at the mean.
The mean of 5,10,15,20, 25 is 15.

So the new number should be 15 too so that the SD does not increase but in fact decreases to get the minimum SD.

Note: When you post a question, please ensure that you write it verbatim. Also, use the standard format of putting down options (A) (B) etc. A - makes one think that the numbers are negative.

For more on SD, check: https://www.veritasprep.com/blog/2012/0 ... deviation/

Responding to a pm:
Quote:
Why option D is wrong ?

SD is minimised not by minimising the numbers but bringing them as close as possible to the average.
Here, the average is 15. The option closest to the average is 15. Hence it is correct.
Adding 10 instead will increase the SD. Check the link on the Veritas Prep blog I have mentioned above.
_________________
Karishma
Veritas Prep GMAT Instructor

Re: Given a list of 5 terms as: 5,10,15,20 and 25. A 6th Term X is added   [#permalink] 22 Mar 2019, 05:59
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