It is currently 23 Mar 2018, 07:27

### 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

# standard deviation

Author Message
Intern
Joined: 18 Dec 2006
Posts: 39

### Show Tags

08 Feb 2009, 02:10

if d is a standard deviation of x, y and z, what is the standard deviation of x+5, y+5 and z+5?
1) d
2) 3d
3) 15d
4) d+5
5) d+15
:evil:

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Senior Manager
Joined: 08 Jan 2009
Posts: 317

### Show Tags

08 Feb 2009, 08:03
1
KUDOS
when each term in the series increases by the same amount,hence the mean also increase the same.The S.D does not change for the series.

Hence Ans : 1) d
Manager
Joined: 27 May 2008
Posts: 197

### Show Tags

08 Feb 2009, 08:25
1
KUDOS
Zaur wrote:

if d is a standard deviation of x, y and z, what is the standard deviation of x+5, y+5 and z+5?
1) d
2) 3d
3) 15d
4) d+5
5) d+15

A

SD will not change if same number is added/sub from the given set of numbers...

Also, if the same number is multiplied/dvided from the given se of the number.. SD also have to be multiplied/dvided...
same case in percentage as well
SVP
Joined: 07 Nov 2007
Posts: 1757
Location: New York

### Show Tags

08 Feb 2009, 17:49
1
KUDOS
agree with A..

standard deviation will not change if you shift values by same number.
_________________

Smiling wins more friends than frowning

Senior Manager
Joined: 02 Nov 2008
Posts: 255

### Show Tags

08 Feb 2009, 17:56
1
KUDOS
Standard Deviation measures the difference between a set of numbers. If all the #'s are increased by the same amount (whether it's 5, 50, or 500) the standard deviation doesn't change.
So yes the answer is A.
Intern
Joined: 18 Dec 2006
Posts: 39

### Show Tags

08 Feb 2009, 23:36
thanks a lot

brgds
Zaur

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: standard deviation   [#permalink] 08 Feb 2009, 23:36
Display posts from previous: Sort by

# standard deviation

Moderator: chetan2u

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne 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®.