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

 It is currently 12 Feb 2016, 10:50

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Normal distribution

Author Message
TAGS:
Senior Manager
Joined: 10 Nov 2010
Posts: 266
Location: India
Concentration: Strategy, Operations
GMAT 1: 520 Q42 V19
GMAT 2: 540 Q44 V21
WE: Information Technology (Computer Software)
Followers: 5

Kudos [?]: 170 [0], given: 22

Normal distribution [#permalink]  24 Mar 2011, 08:45
00:00

Difficulty:

(N/A)

Question Stats:

100% (02:09) correct 0% (00:00) wrong based on 4 sessions
70) if a certain sample of data has a mean of 20.0 and a standard deviation of 3.0,which of the following values is more than 2.5 standard deviation from the mean?

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

the value must be more than 2.5 standard deviation above the mean or below the mean.so the range of values will be

20+7.5 = 27.5
20-7.5 = 12.5

I don't what to do next!!!!!!!!!
[Reveal] Spoiler: OA

_________________

The proof of understanding is the ability to explain it.

Senior Manager
Joined: 17 Mar 2011
Posts: 452
Location: United States (DC)
Concentration: General Management, Technology
GMAT 1: 760 Q49 V45
GPA: 3.37
WE: Information Technology (Consulting)
Followers: 11

Kudos [?]: 177 [0], given: 5

Re: Normal distribution [#permalink]  24 Mar 2011, 08:55
GMATD11 wrote:
70) if a certain sample of data has a mean of 20.0 and a standard deviation of 3.0,which of the following values is more than 2.5 standard deviation from the mean?

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

the value must be more than 2.5 standard deviation above the mean or below the mean.so the range of values will be

20+7.5 = 27.5
20-7.5 = 12.5

I don't what to do next!!!!!!!!!

You've done all the work.

2.5 standard deviations is 7.5, as you've correctly calculated. So you need to find which value is further from 20 than 7.5

If you subtract 12 from 20, you get 8.

8 is more than 7.5

To put it another way, you've calculated the range of values within 2.5 standard deviations as 12.5 through 27.5
You're looking for a value that is outside that range.
Director
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 649
Followers: 37

Kudos [?]: 533 [0], given: 39

Re: Normal distribution [#permalink]  24 Mar 2011, 10:30
2.5 * standard deviation = 2.5 * 3 = 7.5
Only 12.0 is more than 7.5 from the mean.
_________________

Collections:-
PSof OG solved by GC members: http://gmatclub.com/forum/collection-ps-with-solution-from-gmatclub-110005.html
DS of OG solved by GC members: http://gmatclub.com/forum/collection-ds-with-solution-from-gmatclub-110004.html
100 GMAT PREP Quantitative collection http://gmatclub.com/forum/gmat-prep-problem-collections-114358.html
Collections of work/rate problems with solutions http://gmatclub.com/forum/collections-of-work-rate-problem-with-solutions-118919.html
Mixture problems in a file with best solutions: http://gmatclub.com/forum/mixture-problems-with-best-and-easy-solutions-all-together-124644.html

Re: Normal distribution   [#permalink] 24 Mar 2011, 10:30
Similar topics Replies Last post
Similar
Topics:
The average (arithmetic mean) of a normal distribution 1 15 Jul 2012, 15:36
2 The average (arithmetic mean) of a normal distribution of a 11 16 Aug 2010, 10:25
19 The standard deviation of a normal distribution of data is 2 7 16 Aug 2010, 10:15
1 Standard Normal Probability Distribution question 1 06 Jul 2010, 11:49
Pen distribution 1 26 Mar 2010, 06:48
Display posts from previous: Sort by