Standard Deviation.

This topic has expert replies
Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Fri May 07, 2010 4:18 am

Standard Deviation.

by vinaynawani » Sun May 09, 2010 10:46 pm
A certain characteristic in a large population has a distribution that is symmetric about the mean M. If 68 percent of the distribution lies within one standard deviation D of the mean, what percent of the distribution is less than M+D?

A. 16%
B.32%
C. 48%
D. 84%
E. 92%


Hey ppl.....dont know how to go about this 1.
Kindly Help.
Thanx.
Source: — Problem Solving |

User avatar
Legendary Member
Posts: 1022
Joined: Mon Jul 20, 2009 11:49 pm
Location: Gandhinagar
Thanked: 41 times
Followed by:2 members

by shashank.ism » Sun May 09, 2010 10:48 pm
vinaynawani wrote:A certain characteristic in a large population has a distribution that is symmetric about the mean M. If 68 percent of the distribution lies within one standard deviation D of the mean, what percent of the distribution is less than M+D?

A. 16%
B.32%
C. 48%
D. 84%
E. 92%


Hey ppl.....dont know how to go about this 1.
Kindly Help.
Thanx.
isn't this question out of scope of GMAT... some instructor should intervene and suggest.
My Websites:
www.mba.webmaggu.com - India's social Network for MBA Aspirants

www.deal.webmaggu.com -India's online discount, coupon, free stuff informer.

www.dictionary.webmaggu.com - A compact free online dictionary with images.

Nothing is Impossible, even Impossible says I'm possible.

Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Fri May 07, 2010 4:18 am

by vinaynawani » Sun May 09, 2010 10:50 pm
ohh...is it ???

i dont know.
Do let me know if thats d case...

User avatar
Legendary Member
Posts: 1022
Joined: Mon Jul 20, 2009 11:49 pm
Location: Gandhinagar
Thanked: 41 times
Followed by:2 members

by shashank.ism » Sun May 09, 2010 10:58 pm
vinaynawani wrote:ohh...is it ???

i dont know.
Do let me know if thats d case...
I think so but we will have to consult instructors.. wait for the reply of instructor ...btw what is the OS of the question...
My Websites:
www.mba.webmaggu.com - India's social Network for MBA Aspirants

www.deal.webmaggu.com -India's online discount, coupon, free stuff informer.

www.dictionary.webmaggu.com - A compact free online dictionary with images.

Nothing is Impossible, even Impossible says I'm possible.

Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Fri May 07, 2010 4:18 am

by vinaynawani » Sun May 09, 2010 11:02 pm
The O.S. is D.

Legendary Member
Posts: 2326
Joined: Mon Jul 28, 2008 3:54 am
Thanked: 173 times
Followed by:2 members
GMAT Score:710

by gmatmachoman » Sun May 09, 2010 11:25 pm
shashank.ism wrote:
vinaynawani wrote:A certain characteristic in a large population has a distribution that is symmetric about the mean M. If 68 percent of the distribution lies within one standard deviation D of the mean, what percent of the distribution is less than M+D?

A. 16%
B.32%
C. 48%
D. 84%
E. 92%


Hey ppl.....dont know how to go about this 1.
Kindly Help.
Thanx.
isn't this question out of scope of GMAT... some instructor should intervene and suggest.
shashank is true to certain extent. This one revolves ard a statistical rule called 34:14:2 concept( google it for more)

Yeah Answer will be 84%.

These are typical GRE based. Not GMAT ones....

Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Fri May 07, 2010 4:18 am

by vinaynawani » Sun May 09, 2010 11:29 pm
gmatmachoman wrote:
shashank.ism wrote:
vinaynawani wrote:A certain characteristic in a large population has a distribution that is symmetric about the mean M. If 68 percent of the distribution lies within one standard deviation D of the mean, what percent of the distribution is less than M+D?

A. 16%
B.32%
C. 48%
D. 84%
E. 92%


Hey ppl.....dont know how to go about this 1.
Kindly Help.
Thanx.
isn't this question out of scope of GMAT... some instructor should intervene and suggest.
shashank is true to certain extent. This one revolves ard a statistical rule called 34:14:2 concept( google it for more)

Yeah Answer will be 84%.

These are typical GRE based. Not GMAT ones....
k
thanx.

User avatar
Legendary Member
Posts: 526
Joined: Sat Feb 21, 2009 11:47 pm
Location: India
Thanked: 68 times
GMAT Score:680

by harshavardhanc » Sun May 09, 2010 11:45 pm
vinaynawani wrote:
gmatmachoman wrote:
shashank.ism wrote:
vinaynawani wrote:A certain characteristic in a large population has a distribution that is symmetric about the mean M. If 68 percent of the distribution lies within one standard deviation D of the mean, what percent of the distribution is less than M+D?

A. 16%
B.32%
C. 48%
D. 84%
E. 92%


Hey ppl.....dont know how to go about this 1.
Kindly Help.
Thanx.
isn't this question out of scope of GMAT... some instructor should intervene and suggest.
shashank is true to certain extent. This one revolves ard a statistical rule called 34:14:2 concept( google it for more)

Yeah Answer will be 84%.

These are typical GRE based. Not GMAT ones....
k
thanx.
anyway, it's good to know the concepts.

The question says that

--------------------+--------------+------------+--------------------
____16% ___M-D__34%___M__34%__M+D___16%


given : 68% lies between M-D and M+D. So, values beyond (M+D) and (M-D) will constitute 32%, 16-16 distributed on both the sides as shown above.

So, there are 16+34+34 % values less than M+D.

HTH.
Regards,
Harsha