Announcement, 9/22/08: Beat The GMAT is thrilled to welcome Clear Admit and Accepted.com to our community!

Average and median


 
Post new topic   Reply to topic    Beat The GMAT Forum Index -> GMAT Math
View previous topic :: View next topic  
Author Message
kulksnikhil
Rising GMAT Star


Joined: 23 May 2006
Posts: 58

Thanks given: 0
Thanked 0 times in 0 posts

Location: Seoul, Korea

PostPosted: Fri Dec 01, 2006 3:57 am    Post subject: Average and median Reply with quote

I have a general mathematic question.

If Averge of three numbers is say 80 and one of the numbers is 80.. does it mean the median of the three numbers is 80 ???
Back to top


View user's profile Send private message
aim-wsc
Managing Director


Joined: 20 Apr 2006
Posts: 1869

Thanks given: 71
Thanked 28 times in 23 posts

Location: BtG Power House
Target GMAT Score: 801-

PostPosted: Fri Dec 01, 2006 5:17 am    Post subject: Reply with quote

yes.

take a case of
60, 80, 100===>
arithmatic mean =80
&
median =80 too.

but
case 2
75, 80, 100
ave= 85
median= 80

i hope that helps.

Median number has to be in the set

_________________
do you aim-wsc? JohnyCAGE's
Beating GMAT & beyond
1000 SC? |
join in! (Indian IT Males)MBA applicants
Check out our team-page & learn more about me
Back to top


View user's profile Send private message Visit poster's website Yahoo Messenger
rnschmidt
Just gettin' started!


Joined: 07 Nov 2006
Posts: 6

Thanks given: 0
Thanked 0 times in 0 posts


PostPosted: Sat Jan 13, 2007 12:39 pm    Post subject: Reply with quote

what if the set is even? For example:

3,4,5,6


wouldn't the median be 4.5?
Back to top


View user's profile Send private message
aim-wsc
Managing Director


Joined: 20 Apr 2006
Posts: 1869

Thanks given: 71
Thanked 28 times in 23 posts

Location: BtG Power House
Target GMAT Score: 801-

PostPosted: Sat Jan 13, 2007 4:00 pm    Post subject: Reply with quote

rnschmidt wrote:
what if the set is even? For example:

3,4,5,6


wouldn't the median be 4.5?

the value of the median is always there in set of numbers.
4.5 is not in the list so it cannot be. 4.5 is an arithmetic mean average.

_________________
do you aim-wsc? JohnyCAGE's
Beating GMAT & beyond
1000 SC? |
join in! (Indian IT Males)MBA applicants
Check out our team-page & learn more about me
Back to top


View user's profile Send private message Visit poster's website Yahoo Messenger
Stacey Koprince
GMAT Instructor


Joined: 27 Dec 2006
Posts: 1168

Thanks given: 0
Thanked 69 times in 62 posts

Location: Bay Area, California
GMAT Score: 770

PostPosted: Wed Jan 17, 2007 7:20 pm    Post subject: Reply with quote

Actually, the median is only in the set if there is an odd number of terms. If there is an even number of terms, we take the two middle numbers and average them to find the median - so, in this case, the median may not be one of the numbers in the set.

So, for example: 60, 80, 100 has an odd number of terms, so 80 is the median.

1, 4, 6, 7 on the other hand has an even number of terms, so we take the middle two (4 and 6) and average them to get 5 - this is the median even though it is not in the original set of numbers.

So for the original question, 80 is the median because we have an odd number of terms. Our two options are either 80, 80, 80 or something like 78, 80, 82 (the first and third numbers can be anything as long as they average to 80).

If we had an even number of integer terms, which average to 80 and which also include 80, then we could have 80, 80, 80, 80 OR something like 78, 80, 80, 82 OR something like 78, 79, 80, 83. In all 3 cases, the numbers average to 80 but only the first two also have 80 as the median. In the third case, the median is 79.5.

_________________
Stacey Koprince
GMAT Instructor
Director of Corporate Development, Northern California
Manhattan GMAT

Contributor to Beat The GMAT!

Learn more about me
Back to top


View user's profile Send private message Visit poster's website
aim-wsc
Managing Director


Joined: 20 Apr 2006
Posts: 1869

Thanks given: 71
Thanked 28 times in 23 posts

Location: BtG Power House
Target GMAT Score: 801-

PostPosted: Thu Jan 18, 2007 2:02 pm    Post subject: Reply with quote

Stacey Koprince wrote:
In all 3 cases, the numbers average to 80 but only the first two also have 80 as the median. In the third case, the median is 79.5.


Oops i have to brush up some quant skills now Rolling Eyes

_________________
do you aim-wsc? JohnyCAGE's
Beating GMAT & beyond
1000 SC? |
join in! (Indian IT Males)MBA applicants
Check out our team-page & learn more about me
Back to top


View user's profile Send private message Visit poster's website Yahoo Messenger
Display posts from previous:   
Post new topic   Reply to topic    Beat The GMAT Forum Index -> GMAT Math All times are GMT - 7 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum



"GMAT" and other GMAC™ trademarks are registered trademarks of the Graduate Management Admission Council™. The Graduate Management Admission Council™ does not endorse, nor is it affiliated in any way with the owner or any content on this website. The opinions expressed here are solely those of the author or those of the members of this website. Copyright © 2008 BTG Test Prep, LLC. Powered by phpBB © 2001, 2005 phpBB Group.