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

Redeem

gmat prep

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Wed Aug 10, 2011 11:13 am

gmat prep

by vinod192 » Sat Sep 10, 2011 11:46 pm
For a certain examination, a score of 58 was 2 standard deviations below the mean,
and a score of 98 was 3 standard deviations above the mean. What was the mean
score for the examination?
a. 74
b. 76
c. 78
d. 80
e. 82

OA A

solution ASAP
Top
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 31
Joined: Sun Aug 21, 2011 7:12 pm
Thanked: 1 times

by bijoyajj » Sun Sep 11, 2011 12:51 am
m-2d= 58
m+ 3d =98

there for d= 8 hence mean = 74..
Top
User avatar
Junior | Next Rank: 30 Posts
Posts: 24
Joined: Sun Nov 22, 2009 11:12 pm
Thanked: 1 times

by pm » Sun Sep 11, 2011 12:55 am
S.D = Distance from the mean.
Now 98 is +3 S.D and 58 is -2 S.D

Distance between 98-58 = 40 i.e 3+2 S.D so
40/5 = 8 .
Now Check :
Add 8*2 = 16 +58 = 74
8*3 = 98- 24 = 74.
A
Top
Post new topic Post Reply
• Page 1 of 1