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

It is currently 27 Sep 2016, 05:10
GMAT Club Tests

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

The residents of Town X participated in a survey to

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Director
Director
avatar
Joined: 17 Sep 2005
Posts: 924
Followers: 3

Kudos [?]: 67 [0], given: 0

The residents of Town X participated in a survey to [#permalink]

Show Tags

New post 09 Sep 2007, 16:32
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

The residents of Town X participated in a survey to determine the number of hours per week each resident spent watching television. The distribution of the result of the survey had a mean of 21 hours and a standard deviation of 6 hours. The number of hours that John, a resident of Town X, watched television last week was between 1 and 2 standard deviations below the mean. Which of the following could be the number of hours that John watched television last week?

1. 30
2. 20
3. 18
4. 12
5. 6

- Brajesh
CEO
CEO
User avatar
Joined: 29 Mar 2007
Posts: 2583
Followers: 19

Kudos [?]: 387 [0], given: 0

Re: PS - Standard Deviation [#permalink]

Show Tags

New post 09 Sep 2007, 21:45
b14kumar wrote:
The residents of Town X participated in a survey to determine the number of hours per week each resident spent watching television. The distribution of the result of the survey had a mean of 21 hours and a standard deviation of 6 hours. The number of hours that John, a resident of Town X, watched television last week was between 1 and 2 standard deviations below the mean. Which of the following could be the number of hours that John watched television last week?

1. 30
2. 20
3. 18
4. 12
5. 6

- Brajesh


21-6=15-6=9, So its btwn 15 and 9. Thus 12.

Ans D.
Senior Manager
Senior Manager
User avatar
Joined: 27 Aug 2007
Posts: 253
Followers: 1

Kudos [?]: 11 [0], given: 0

 [#permalink]

Show Tags

New post 09 Sep 2007, 22:49
21 - 6*1=15
21 - 6*2=9

9<x<15

Ans: D:12
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5062
Location: Singapore
Followers: 30

Kudos [?]: 329 [0], given: 0

 [#permalink]

Show Tags

New post 09 Sep 2007, 22:51
1 SD below mean = 21-6 = 15
2 SD below mean = 21-12 = 9

So range = 9-15 hours. Only Choice D fits.
Director
Director
avatar
Joined: 17 Sep 2005
Posts: 924
Followers: 3

Kudos [?]: 67 [0], given: 0

 [#permalink]

Show Tags

New post 10 Sep 2007, 06:18
Guys, can somebody please elaborate the concept/formula used here?

Thanks,
Brajesh
Manager
Manager
avatar
Joined: 29 Aug 2007
Posts: 110
Followers: 1

Kudos [?]: 5 [0], given: 0

 [#permalink]

Show Tags

New post 10 Sep 2007, 07:30
Fistail

You have applied a formulae here to calculate the SD.. Can you tell me what forumalae that is??
Director
Director
avatar
Joined: 17 Sep 2005
Posts: 924
Followers: 3

Kudos [?]: 67 [0], given: 0

 [#permalink]

Show Tags

New post 11 Sep 2007, 22:34
Do we need to use some formula for this question?
Somebody please explain....

- Brajesh
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5062
Location: Singapore
Followers: 30

Kudos [?]: 329 [0], given: 0

 [#permalink]

Show Tags

New post 11 Sep 2007, 23:08
b14kumar wrote:
Do we need to use some formula for this question?
Somebody please explain....

- Brajesh


Standard deviation curve is centered at the mean. Take a look at this plot and you will see what I mean...

http://en.wikipedia.org/wiki/Image:Standard_deviation_diagram.svg
Director
Director
User avatar
Joined: 03 May 2007
Posts: 886
Schools: University of Chicago, Wharton School
Followers: 6

Kudos [?]: 163 [0], given: 7

 [#permalink]

Show Tags

New post 11 Sep 2007, 23:28
b14kumar wrote:
Do we need to use some formula for this question?
Somebody please explain....

- Brajesh


though there are formulas but the question clearly syas that "what is the value in between 1 and 2 sd"?
Director
Director
avatar
Joined: 11 Jun 2007
Posts: 931
Followers: 1

Kudos [?]: 161 [0], given: 0

 [#permalink]

Show Tags

New post 11 Sep 2007, 23:43
also got D for the answer. The question is asking for a possible hour. We know from the question that the possible range is 1-2 SD below the mean of 21 hrs.

So the possible range is:

1 SD below: 21-6 = 15
2 SD below: 21-12 = 9

So between 9-15 hours. The only answer within this range is 12 (D).
Director
Director
avatar
Joined: 17 Sep 2005
Posts: 924
Followers: 3

Kudos [?]: 67 [0], given: 0

 [#permalink]

Show Tags

New post 13 Sep 2007, 19:27
Thanks guys.

OA is D (12).

- Brajesh
  [#permalink] 13 Sep 2007, 19:27
Display posts from previous: Sort by

The residents of Town X participated in a survey to

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| 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®.