MEAN was quite mean !

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 24
Joined: Sat Sep 20, 2008 10:06 am
Location: JAPAN

MEAN was quite mean !

by ravikirancheni » Thu Jan 15, 2009 5:59 am
Where did i flunk ?

It says ..1 SD => from 9.7 to 10.3
That gives us 7 numbers out of 8 i,e 85%

[spoiler]OA : 75 %[/spoiler]
Attachments
SD.jpg

Master | Next Rank: 500 Posts
Posts: 145
Joined: Mon Sep 29, 2008 1:14 am
Thanked: 13 times

Re: MEAN was quite mean !

by mental » Thu Jan 15, 2009 6:18 am
ravikirancheni wrote:Where did i flunk ?

It says ..1 SD => from 9.7 to 10.3
That gives us 7 numbers out of 8 i,e 85%

[spoiler]OA : 75 %[/spoiler]
Please check again:
The two numbers out of range are 9.4 and 10.5

so 6 numbers in range

6/8 = 75%

Junior | Next Rank: 30 Posts
Posts: 24
Joined: Sat Sep 20, 2008 10:06 am
Location: JAPAN

by ravikirancheni » Thu Jan 15, 2009 6:21 am
Blunder on my part !!!!!
gosh ,,,,,No clemency for such on Real test !
Thanks a lot MENTAL !!!

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2621
Joined: Mon Jun 02, 2008 3:17 am
Location: Montreal
Thanked: 1090 times
Followed by:355 members
GMAT Score:780

by Ian Stewart » Thu Jan 15, 2009 8:51 am
You actually don't even need to look at the set here, since only one answer is possible. The question asks "what percent of the 8 numbers..." so the only possible answers would be:

0/8 = 0 %
...
5/8 = 62.5 %
6/8 = 75 %
7/8 = 87.5 %
8/8 = 100 %

There's only one answer that could possibly be right: D.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com