Find all School-related info fast with the new School-Specific MBA Forum

It is currently 22 Oct 2014, 00:02

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Standard deviation and Mean problem

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
User avatar
Joined: 27 Feb 2010
Posts: 106
Location: Denver
Followers: 1

Kudos [?]: 119 [0], given: 14

Standard deviation and Mean problem [#permalink] New post 23 Apr 2010, 16:02
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

80% (01:18) correct 20% (00:00) wrong based on 8 sessions
if a certain sample of data has a mean of 20.0 and a standard deviation of 3.0, which of the folllowing values is more than 2.5 standard deviations from the mean?

a.12.0
b.13.5
c.17.0
d.23.5
e.26.5

Can someone please explain the solution for this problem?
1 KUDOS received
VP
VP
avatar
Joined: 05 Mar 2008
Posts: 1477
Followers: 11

Kudos [?]: 201 [1] , given: 31

Re: Standard deviation and Mean problem [#permalink] New post 23 Apr 2010, 16:05
1
This post received
KUDOS
zz0vlb wrote:
if a certain sample of data has a mean of 20.0 and a standard deviation of 3.0, which of the folllowing values is more than 2.5 standard deviations from the mean?

a.12.0
b.13.5
c.17.0
d.23.5
e.26.5

Can someone please explain the solution for this problem?


3*2.5 = 7.5

Low end: 12.5
Upper end: 27.5

All fall within range except A
Manager
Manager
User avatar
Joined: 27 Feb 2010
Posts: 106
Location: Denver
Followers: 1

Kudos [?]: 119 [0], given: 14

Re: Standard deviation and Mean problem [#permalink] New post 23 Apr 2010, 16:13
Thank you for the quick reply lagomez. +1 Kudos to you.
Expert Post
SVP
SVP
avatar
Status: Graduated
Affiliations: HEC
Joined: 28 Sep 2009
Posts: 1638
Concentration: Economics, Finance
GMAT 1: 730 Q48 V44
Followers: 86

Kudos [?]: 490 [0], given: 432

Premium Member
Re: Standard deviation and Mean problem [#permalink] New post 06 Jul 2010, 14:35
Expert's post
The mean (average) equals 20, and the standard deviation equals 3. For standard deviation, remember to consider numbers above and below the mean.

One standard deviation includes all numbers that fall into 17 to 23. This is determined by adding and subtracting 3 from 20. In other words, 20 + 3 = 23, and 20 - 3 = 17. We can eliminate C.

Two standard deviations identifies the set of numbers that fall into 14 ( 20 - 3 - 3) to 26 (20 + 3 + 3). We can eliminate D.

2.5 standard deviations results in 12.5 to 27.5. We can eliminate B and E. Hence, A.

Lagomez, of course, has already shown us a faster way. :wink:
_________________

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Re: Standard deviation and Mean problem   [#permalink] 06 Jul 2010, 14:35
    Similar topics Author Replies Last post
Similar
Topics:
3 Experts publish their posts in the topic Properties of Mean, Standard Deviation brobeedle 4 08 Apr 2014, 07:10
1 Experts publish their posts in the topic The arithmetic mean and standard deviation of a certain norm ronny13 10 08 Mar 2010, 01:37
2 standard deviation is so mean ppp21 6 04 Dec 2009, 03:47
statistics - mean and standard deviation mpjena 8 28 May 2007, 15:13
Word Problem - standard deviation above720 1 18 May 2007, 15:51
Display posts from previous: Sort by

Standard deviation and Mean problem

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.