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

It is currently 29 Aug 2014, 10:46

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

m05#07

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
1 KUDOS received
Manager
Manager
avatar
Joined: 14 May 2008
Posts: 57
Schools: Wharton (WEMBA East)
Followers: 1

Kudos [?]: 15 [1] , given: 1

GMAT Tests User
m05#07 [#permalink] New post 14 Oct 2008, 18:12
1
This post received
KUDOS
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

77% (01:26) correct 23% (00:29) wrong based on 209 sessions
Which of the following sets has the standard deviation greater than the standard deviation of set X={-19, -17, -15, -13, -11}

I. A={1, 3, 5, 7, 9}

II. B={2, 4, 6, 8, 10}

III. C={1, -1, -3, -5, -7}

A. Set A only
B. Set B only
C. Set C only
D. Sets A, B and C
E. None of the sets


Source: GMAT Club Tests - hardest GMAT questions
[Reveal] Spoiler: OA

Last edited by Bunuel on 14 Nov 2013, 06:21, edited 1 time in total.
Updated
Kaplan GMAT Prep Discount CodesKnewton GMAT Discount CodesVeritas Prep GMAT Discount Codes
Expert Post
3 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 25204
Followers: 3418

Kudos [?]: 25024 [3] , given: 2699

Re: m05#07 [#permalink] New post 19 Nov 2012, 06:55
3
This post received
KUDOS
Expert's post
scorcho wrote:
Which set has the greatest standard deviation?

I. 1, 3, 5, 7, 9
II. 2, 4, 6, 8, 10
III. 1, -1, -3, -5, -7

(A) I
(B) II
(C) III
(D) I and II
(E) none

[Reveal] Spoiler: OA
E

Source: GMAT Club Tests - hardest GMAT questions

Current explanation implies one would calculate the stddev for the sequence.

Alternate explanation: They're all just skip+1 sets of the form f(n)=kn+x, k=2, no need to calculate stddev.


BELOW IS REVISED VERSION OF THIS QUESTION:

Which of the following sets has the standard deviation greater than the standard deviation of set X={-19, -17, -15, -13, -11}

I. A={1, 3, 5, 7, 9}

II. B={2, 4, 6, 8, 10}

III. C={1, -1, -3, -5, -7}

A. Set A only
B. Set B only
C. Set C only
D. Sets A, B and C
E. None of the sets

If we add or subtract a constant to each term in a set the standard deviation will not change.

Since each set can be obtained by adding some constant to each term of set X (20 for set A, 21 for set B and 12 for set C), then the standard deviations of all sets are the same.

Answer: E.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Manager
Manager
avatar
Joined: 07 May 2013
Posts: 109
Followers: 0

Kudos [?]: 8 [0], given: 1

Re: m05#07 [#permalink] New post 22 Nov 2013, 13:44
Buneul, the concept of standard deviation is alien to many including me. Can please post a link to a page explaining this concept in detail.
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 25204
Followers: 3418

Kudos [?]: 25024 [0], given: 2699

Re: m05#07 [#permalink] New post 22 Nov 2013, 13:45
Expert's post
madn800 wrote:
Buneul, the concept of standard deviation is alien to many including me. Can please post a link to a page explaining this concept in detail.


Theory on Statistics and Sets problems: math-standard-deviation-87905.html

All DS Statistics and Sets problems to practice: search.php?search_id=tag&tag_id=34
All PS Statistics and Sets problems to practice: search.php?search_id=tag&tag_id=55

_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Re: m05#07   [#permalink] 22 Nov 2013, 13:45
Display posts from previous: Sort by

m05#07

  Question banks Downloads My Bookmarks Reviews Important topics  

Moderators: Bunuel, WoundedTiger



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®.