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

It is currently 30 Aug 2016, 13:55
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

If a certain sample of data has a mean of 20.0 and a standard deviatio

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

1 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 10 Nov 2010
Posts: 267
Location: India
Concentration: Strategy, Operations
GMAT 1: 520 Q42 V19
GMAT 2: 540 Q44 V21
WE: Information Technology (Computer Software)
Followers: 5

Kudos [?]: 239 [1] , given: 22

If a certain sample of data has a mean of 20.0 and a standard deviatio [#permalink]

Show Tags

New post 24 Mar 2011, 09:45
1
This post received
KUDOS
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

77% (01:43) correct 23% (00:34) wrong based on 39 sessions

HideShow timer Statistics

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

[Reveal] Spoiler:
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!!!!!!!!!


OPEN DISCUSSION OF THIS QUESTION IS HERE: if-a-certain-sample-of-data-has-a-mean-of-20-0-and-a-130542.html
[Reveal] Spoiler: OA

_________________

The proof of understanding is the ability to explain it.

Senior Manager
Senior Manager
avatar
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 [?]: 181 [0], given: 5

Re: If a certain sample of data has a mean of 20.0 and a standard deviatio [#permalink]

Show Tags

New post 24 Mar 2011, 09:55
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.

The answer is (a).

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
Director
User avatar
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 649
Followers: 39

Kudos [?]: 729 [0], given: 39

Re: If a certain sample of data has a mean of 20.0 and a standard deviatio [#permalink]

Show Tags

New post 24 Mar 2011, 11:30
2.5 * standard deviation = 2.5 * 3 = 7.5
Only 12.0 is more than 7.5 from the mean.
Answer (A).
_________________

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

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 11152
Followers: 512

Kudos [?]: 134 [0], given: 0

Premium Member
Re: If a certain sample of data has a mean of 20.0 and a standard deviatio [#permalink]

Show Tags

New post 21 Feb 2016, 12:13
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 34511
Followers: 6303

Kudos [?]: 79972 [0], given: 10022

Re: If a certain sample of data has a mean of 20.0 and a standard deviatio [#permalink]

Show Tags

New post 21 Feb 2016, 13:54
Expert's post
2
This post was
BOOKMARKED
GMATD11 wrote:
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

[Reveal] Spoiler:
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!!!!!!!!!


Value is more than 2.5SD from the mean means that the distance between the mean and the value must be more than 2.5*SD=7.5. So the value must be either less than 20-7.5=12.5 or more than 20+7.5=27.5.

Answer: A.

OPEN DISCUSSION OF THIS QUESTION IS HERE: if-a-certain-sample-of-data-has-a-mean-of-20-0-and-a-130542.html
_________________

New to the Math Forum?
Please read this: All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Re: If a certain sample of data has a mean of 20.0 and a standard deviatio   [#permalink] 21 Feb 2016, 13:54
    Similar topics Author Replies Last post
Similar
Topics:
4 Experts publish their posts in the topic If a certain sample of data has a mean of 24.0 and the value Raghunathnallu 6 28 May 2014, 10:05
4 Experts publish their posts in the topic A data set with a mean of 60 has a standard deviation of 3.5 Mountain14 6 04 Jan 2014, 19:54
10 Experts publish their posts in the topic If a certain sample of data has a mean of 20.0 and a sapna44 9 11 Apr 2012, 01:46
15 Experts publish their posts in the topic If a certain sample of data has a mean of 20.0 and a enigma123 8 19 Feb 2012, 16:04
16 Experts publish their posts in the topic A certain list of 100 data has an average (arithmetic mean) Gmatter111 8 08 Dec 2009, 03:54
Display posts from previous: Sort by

If a certain sample of data has a mean of 20.0 and a standard deviatio

  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®.