|
Author |
Message |
|
TAGS:
|
|
|
Director
Joined: 09 Aug 2006
Posts: 531
Followers: 2
Kudos [?]:
20
[0], given: 0
|
Standard deviation - PS - GMAT Prrep [#permalink]
 06 Nov 2006, 08:05
Question Stats:
0% (00:00) correct
 0% (00:00) wrong based on 0 sessions
How to solve this ..?
Attachments
d.JPG [ 14.35 KiB | Viewed 201 times ]
|
|
|
|
|
|
|
Manager
Joined: 01 Nov 2006
Posts: 70
Followers: 1
Kudos [?]:
0
[0], given: 0
|
No solving - standard deviation is invariant to adding a constant. Try proving it. It's very easy proof.
|
|
|
|
|
|
Senior Manager
Joined: 05 Oct 2006
Posts: 272
Followers: 1
Kudos [?]:
1
[0], given: 0
|
Re: Standard deviation - PS - GMAT Prrep [#permalink]
06 Nov 2006, 10:29
mean for new set of values = m+5.....if m istrhe mean for x,y and z...'
sd= ((x+5) - (m+5))^2+......= d
aans is d..choice a
|
|
|
|
|
|
Manager
Joined: 04 Oct 2006
Posts: 192
Followers: 1
Kudos [?]:
1
[0], given: 0
|
Yeah standard deviation will not change....if you want to know the reasoning behind it look up how to solve for a standard deviation and then plug in some numbers. It then becomes clear why adding a constant does not change the SD but multiplting it by something can.
|
|
|
|
|
|
Manager
Joined: 01 Apr 2006
Posts: 98
Followers: 2
Kudos [?]:
5
[0], given: 0
|
I just picked simple numbers for x y z, such as 1 2 3
Add 5 to each, same Std Dev.
A) d
|
|
|
|
|
|
VP
Joined: 15 Jul 2004
Posts: 1482
Schools: Wharton (R2 - submitted); HBS (R2 - submitted); IIMA (admitted for 1 year PGPX)
Followers: 10
Kudos [?]:
61
[0], given: 13
|
Right.. adding a constant no to all three wouldn't change the standard deviation.
|
|
|
|
|
|
Director
Joined: 09 Aug 2006
Posts: 531
Followers: 2
Kudos [?]:
20
[0], given: 0
|
Got it .. Thanks everyone ..
Got a very imp concept cleared ..
Regds,
Amit
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
close
