SD

This topic has expert replies
User avatar
Master | Next Rank: 500 Posts
Posts: 117
Joined: Wed Dec 30, 2009 1:57 pm
Location: India
Thanked: 4 times
Followed by:1 members

SD

by abhi332 » Wed Feb 24, 2010 11:26 am
E is a collection of four odd integers and the greatest difference between any two integers in E is 4. The standard deviation of E must be one of how many numbers?

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7
What you think, you become.
Source: — Problem Solving |

User avatar
Legendary Member
Posts: 1275
Joined: Thu Sep 21, 2006 11:13 pm
Location: Arabian Sea
Thanked: 125 times
Followed by:2 members

by ajith » Wed Feb 24, 2010 11:52 am
abhi332 wrote:E is a collection of four odd integers and the greatest difference between any two integers in E is 4. The standard deviation of E must be one of how many numbers?

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7
Say the numbers are a,b,c,d

One possibility is a=b=c, d= a+4
another is a=b; c=d ; c = a+4
another is a=b , c = a+2; d=a+4
Another is a, b=c=a+2, d= a+4
another is a, b=a+2, c=d=a+4
another is a, b=c=d=a+4

6 possibilities I see, Not quite sure though
Always borrow money from a pessimist, he doesn't expect to be paid back.