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

 It is currently 04 May 2015, 04:56

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# from Veritas ProjectGMAT. One of their tips with no example

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
CEO
Joined: 21 Jan 2007
Posts: 2764
Location: New York City
Followers: 9

Kudos [?]: 349 [0], given: 4

from Veritas ProjectGMAT. One of their tips with no example [#permalink]  15 May 2007, 18:45
from Veritas ProjectGMAT. One of their tips with no example shown...

"Adding or subtracting a constant from each element in the set has no effect on the standard deviation"

Can someone elaborate on this?
 Veritas Prep GMAT Discount Codes Knewton GMAT Discount Codes Kaplan GMAT Prep Discount Codes
Director
Joined: 26 Feb 2006
Posts: 905
Followers: 4

Kudos [?]: 52 [0], given: 0

Re: standard deviation [#permalink]  15 May 2007, 18:52
bmwhype2 wrote:
from Veritas ProjectGMAT. One of their tips with no example shown...

"Adding or subtracting a constant from each element in the set has no effect on the standard deviation"

Can someone elaborate on this?

suppose the value of x are: 10, 11, 13, 15, and 20
now you deduct 5 from each, then x values are: 5, 6, 8, 10 and 15
now you add 5 on each, then values of x are: 15, 16, 18, 20 and 25

the sd is 3.96 in all cases.
CEO
Joined: 21 Jan 2007
Posts: 2764
Location: New York City
Followers: 9

Kudos [?]: 349 [0], given: 4

[#permalink]  15 May 2007, 18:53
nevermind. figured it out...

set a (1,2,3,4,5,) Standard deviation of 1
set b (5,6,7,8,9) all terms n+5 . standard deviation of 1

therefore, sd is the same.
Manager
Joined: 30 Mar 2007
Posts: 220
Followers: 1

Kudos [?]: 3 [0], given: 0

[#permalink]  15 May 2007, 21:26
This happens coz if we subtract or add some constant number from a set of numbers then the average also decreases or increases respectively by same figure thus keeping the difference of numbers and average constant.
CEO
Joined: 21 Jan 2007
Posts: 2764
Location: New York City
Followers: 9

Kudos [?]: 349 [0], given: 4

[#permalink]  15 May 2007, 21:37
apache wrote:
This happens coz if we subtract or add some constant number from a set of numbers then the average also decreases or increases respectively by same figure thus keeping the difference of numbers and average constant.

yea. just shifting the entire set (all the elements) by the same ratio or amount.
[#permalink] 15 May 2007, 21:37
Similar topics Replies Last post
Similar
Topics:
183 Tips and Hints for Specific Quant Topics (with Examples) 2 03 Jun 2014, 05:01
Project GMAT or Veritas Probability and Combranatrics Book? 5 13 Dec 2011, 20:24
8 Interview tips - from one novice to another 11 13 Oct 2009, 18:01
Leadership example: which one? 2 24 Nov 2006, 07:22
Book: Project GMAT by Veritas 1 29 Dec 2005, 12:59
Display posts from previous: Sort by

# from Veritas ProjectGMAT. One of their tips with no example

 Question banks Downloads My Bookmarks Reviews Important topics

 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®.