mean

BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

divya23: Master | Next Rank: 500 Posts; Posts: 113; Joined: Mon Apr 26, 2010 8:58 am; Thanked: 2 times; Followed by:14 members

by divya23 » Sun Jun 19, 2011 1:47 am

mean = 20
s.d = 3
find the number more than 2.5sd from mean
12
13.5
17
23.5
26.5

Source: Beat The GMAT — Problem Solving | Sun Jun 19, 2011 1:47 am

Frankenstein: Legendary Member; Posts: 1448; Joined: Tue May 17, 2011 9:55 am; Location: India; Thanked: 375 times; Followed by:53 members

by Frankenstein » Sun Jun 19, 2011 2:59 am

Hi,
mean+2.5sd = 20+(2.5)*3 = 27.5
mean-2.5sd = 20-(2.5)*3 = 12.5
Only 12 is outside the range of 2.5sd from mean

Hence, A

Cheers!

Things are not what they appear to be... nor are they otherwise

amit2k9: Master | Next Rank: 500 Posts; Posts: 461; Joined: Tue May 10, 2011 9:09 am; Location: pune; Thanked: 36 times; Followed by:3 members

by amit2k9 » Sun Jun 19, 2011 3:33 am

2.5 * 3 = 7.5
20-7.5 = 13.5
20+7.5= 27.5

A fits in.

For Understanding Sustainability,Green Businesses and Social Entrepreneurship visit -https://aamthoughts.blocked/
(Featured Best Green Site Worldwide-https://bloggers.com/green/popular/page2)

• Page 1 of 1