Find all School-related info fast with the new School-Specific MBA Forum

It is currently 27 Aug 2014, 11:34

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

A certain list of 100 data has an average (arithmetic mean)

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 26 Feb 2008
Posts: 37
Followers: 0

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

A certain list of 100 data has an average (arithmetic mean) [#permalink] New post 22 Mar 2008, 16:17
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
A certain list of 100 data has an average (arithmetic mean) of 6 and a standard deviation of d, where d is positive. Which of the following pairs of data, when added to the list must result in a list of 102 data with standard deviation less than d?

(A) -6 & 0
(B) 0 & 0
(C) 0 & 6
(D) 0 & 12
(E) 6 & 6

Pls explain. Thanks.
Senior Manager
Senior Manager
avatar
Joined: 15 Aug 2007
Posts: 255
Schools: Chicago Booth
Followers: 1

Kudos [?]: 53 [0], given: 0

Re: PS:Standard Deviation [#permalink] New post 22 Mar 2008, 18:02
E - Same question was posted a day ago. SD depends on the deviation from mean, so for values in E the deviations are zero which is the minimum we can get.
SVP
SVP
avatar
Joined: 04 May 2006
Posts: 1941
Schools: CBS, Kellogg
Followers: 16

Kudos [?]: 274 [0], given: 1

Premium Member CAT Tests
Re: PS:Standard Deviation [#permalink] New post 22 Mar 2008, 18:59
sreehari wrote:
E - Same question was posted a day ago. SD depends on the deviation from mean, so for values in E the deviations are zero which is the minimum we can get.


Sorry guys, can you give more discription? Why "values in E the deviations are zero" make the new SD less than the old?
_________________

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Manager
Manager
avatar
Joined: 02 Mar 2008
Posts: 212
Concentration: Finance, Strategy
Followers: 1

Kudos [?]: 38 [0], given: 1

GMAT Tests User
Re: PS:Standard Deviation [#permalink] New post 22 Mar 2008, 19:07
add 6 to the population of mean 6 does not change it mean
so the 2 new squares of difference are 0 -> reduce ur SD (divide by N+2)
SVP
SVP
avatar
Joined: 04 May 2006
Posts: 1941
Schools: CBS, Kellogg
Followers: 16

Kudos [?]: 274 [0], given: 1

Premium Member CAT Tests
Re: PS:Standard Deviation [#permalink] New post 22 Mar 2008, 19:19
AlbertNTN wrote:
add 6 to the population of mean 6 does not change it mean
so the 2 new squares of difference are 0 -> reduce ur SD (divide by N+2)


Thank you,

I plan to make a stupid calculation.
:oops:
_________________

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Re: PS:Standard Deviation   [#permalink] 22 Mar 2008, 19:19
    Similar topics Author Replies Last post
Similar
Topics:
6 Experts publish their posts in the topic A certain list of 100 data has an average (arithmetic mean) Gmatter111 6 08 Dec 2009, 02:54
A certain list of 100 data has an avarage (arithmetic mean) Snayt 3 22 Mar 2008, 03:58
A certain list of 100 data has an average (arithmetic mean) jp888 1 28 Aug 2007, 05:12
A certain list of 100 data has an average (arithmetic mean) shehreenquayyum 3 04 Nov 2006, 18:48
A certain list of 100 data has an average (arithmetic mean) ffgmat 4 22 May 2006, 04:03
Display posts from previous: Sort by

A certain list of 100 data has an average (arithmetic mean)

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.