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

 It is currently 07 Jul 2015, 21:13

### 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

# GMATPrep Question on SD

Author Message
TAGS:
Manager
Joined: 28 Jan 2006
Posts: 118
Followers: 1

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

GMATPrep Question on SD [#permalink]  19 Aug 2006, 02:06
Please solve this GMATPrep Question : kindly ignore the answer choice marked in the screen shot.
Attachments

math_SD.JPG [ 60.55 KiB | Viewed 428 times ]

_________________

All the best!!
shinewine

 Kaplan GMAT Prep Discount Codes Knewton GMAT Discount Codes Manhattan GMAT Discount Codes
Director
Joined: 17 Jul 2006
Posts: 716
Followers: 1

Kudos [?]: 9 [0], given: 0

same amount is removed from each tank and so the Standard deviation remains same after this remove.

A says SD still same.

B talks about average of 6 tanks 63. Not sufficient.
Manager
Joined: 28 Jan 2006
Posts: 118
Followers: 1

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

same amount is removed from each tank and so the Standard deviation remains same after this remove.

A says SD still same.

B talks about average of 6 tanks 63. Not sufficient.

also can you please guide me ..how can i improve on the concepts..of SD
_________________

All the best!!
shinewine

CEO
Joined: 20 Nov 2005
Posts: 2910
Schools: Completed at SAID BUSINESS SCHOOL, OXFORD - Class of 2008
Followers: 19

Kudos [?]: 133 [0], given: 0

A

SD is measure of the variations of the elements of set with respect to mean.

Lets say water tanks have
10 , 20 , 30, 40, 50 , 60 gallons
Now after removing 30% from each we have
7,14,21,28,35,42

As all elements are reduced by 30%, the mean will also be reduced by 30%. So the variation of elements with respect to the new mean is also same. So SD will remain the same.

statement 2 don't tell the scenario after the removal. So its INSUFF.
_________________

SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008

Manager
Joined: 28 Jan 2006
Posts: 118
Followers: 1

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

ps_dahiya wrote:
A

SD is measure of the variations of the elements of set with respect to mean.

Lets say water tanks have
10 , 20 , 30, 40, 50 , 60 gallons
Now after removing 30% from each we have
7,14,21,28,35,42

As all elements are reduced by 30%, the mean will also be reduced by 30%. So the variation of elements with respect to the new mean is also same. So SD will remain the same.

statement 2 don't tell the scenario after the removal. So its INSUFF.

Thank you.. now i get it.. i wasted some 5 minute on this problm.. while doing the GMATPrep test..
_________________

All the best!!
shinewine

Similar topics Replies Last post
Similar
Topics:
GMATPrep 2 - SD question 5 01 Jun 2008, 15:16
Mean, Medium, SD Question 6 27 Mar 2007, 14:30
GMATPrep Question 5 16 Jun 2006, 09:27
GMATPREP QUESTION 3 02 Jun 2006, 10:44
GMATPrep Question 6 14 May 2006, 17:48
Display posts from previous: Sort by