Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 22 May 2017, 22:37

### 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

# Gmat Prep Standard deviation

Author Message
Senior Manager
Joined: 23 May 2008
Posts: 416
Followers: 5

Kudos [?]: 394 [0], given: 14

### Show Tags

29 Sep 2009, 02:21
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 100% (00:00) wrong based on 1 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

No idea how to solve this...........
Attachments

statistics.jpg [ 58.29 KiB | Viewed 1396 times ]

Intern
Joined: 07 Sep 2009
Posts: 6
Followers: 0

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

Re: Gmat Prep Standard deviation [#permalink]

### Show Tags

29 Sep 2009, 03:46
I'm not completely sure but I think 6 and 6.

Standard deviation is lower when data points of the set are closer to the mean so if you add two data points which are the same as the mean it should result in a lower SD.
Senior Manager
Joined: 23 Jun 2009
Posts: 361
Location: Turkey
Schools: UPenn, UMich, HKS, UCB, Chicago
Followers: 5

Kudos [?]: 132 [0], given: 80

Re: Gmat Prep Standard deviation [#permalink]

### Show Tags

29 Sep 2009, 03:46
E

Std. Dev. = sqrt(((a1-mean)^2+(a2-mean)^2....+(an-mean)^2))/n) where an = elements of set.

When we add 2 elements to the set which are exactly the same as mean. We do not change the nominator of the formula and we increase the denominator. Thus, we decrease the std. dev.
Senior Manager
Joined: 23 May 2008
Posts: 416
Followers: 5

Kudos [?]: 394 [0], given: 14

Re: Gmat Prep Standard deviation [#permalink]

### Show Tags

29 Sep 2009, 05:57
fiercepoint wrote:
I'm not completely sure but I think 6 and 6.

Standard deviation is lower when data points of the set are closer to the mean so if you add two data points which are the same as the mean it should result in a lower SD.

I got what u are trying to say.....thanks the OA is E
Senior Manager
Joined: 23 May 2008
Posts: 416
Followers: 5

Kudos [?]: 394 [0], given: 14

Re: Gmat Prep Standard deviation [#permalink]

### Show Tags

29 Sep 2009, 05:58
maliyeci wrote:
E

Std. Dev. = sqrt(((a1-mean)^2+(a2-mean)^2....+(an-mean)^2))/n) where an = elements of set.

When we add 2 elements to the set which are exactly the same as mean. We do not change the nominator of the formula and we increase the denominator. Thus, we decrease the std. dev.

Thanks... the OA is E
Director
Joined: 01 Jan 2008
Posts: 624
Followers: 5

Kudos [?]: 184 [0], given: 1

Re: Gmat Prep Standard deviation [#permalink]

### Show Tags

29 Sep 2009, 06:30
I wouldn't even worry about formula of standard deviation. Standard deviation is a measure of deviation from the mean. If you add datapoints that are very close to the mean, standard deviation decreases. If you add datapoints that are far away from the mean, standard deviation increases.
Manager
Joined: 14 Dec 2008
Posts: 166
Followers: 1

Kudos [?]: 25 [0], given: 39

Re: Gmat Prep Standard deviation [#permalink]

### Show Tags

29 Sep 2009, 11:36
IMO E , avg/mean is 6, standard deviation is displacement from avg/mean , to reduce the standard deviation, the most appropriate value is avg itself.. hope i did it right.
Senior Manager
Joined: 23 May 2008
Posts: 416
Followers: 5

Kudos [?]: 394 [0], given: 14

Re: Gmat Prep Standard deviation [#permalink]

### Show Tags

29 Sep 2009, 21:32
Thanks guyzz you all are perfectly right...
Re: Gmat Prep Standard deviation   [#permalink] 29 Sep 2009, 21:32
Display posts from previous: Sort by