Author 
Message 
TAGS:

Hide Tags

Director
Joined: 29 Nov 2012
Posts: 828

The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
Updated on: 09 Jan 2013, 03:43
1
This post received KUDOS
14
This post was BOOKMARKED
Question Stats:
71% (01:30) correct 29% (01:38) wrong based on 360 sessions
HideShow timer Statistics
X frequency 1 3 2 1 3 3 4 1 5 3 6 1 7 3 The variable x takes on integer values between 1 and 7 inclusive as shown above. What is the probability that the absolute value of the difference between the mean of the distribution which is 4 and a randomly chosen value of x will be greater than 3/2? A) 8/15 B) 4/7 C) 4/5 D) 6/7 E) 8/7 Attachment:
DSCN0392.JPG [ 1002.27 KiB  Viewed 1113 times ]
Official Answer and Stats are available only to registered users. Register/ Login.
_________________
Click +1 Kudos if my post helped...
Amazing Free video explanation for all Quant questions from OG 13 and much more http://www.gmatquantum.com/og13th/
GMAT Prep software What if scenarios http://gmatclub.com/forum/gmatprepsoftwareanalysisandwhatifscenarios146146.html
Originally posted by fozzzy on 08 Jan 2013, 21:25.
Last edited by fozzzy on 09 Jan 2013, 03:43, edited 1 time in total.



VP
Joined: 02 Jul 2012
Posts: 1197
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
08 Jan 2013, 22:26
6
This post received KUDOS
1
This post was BOOKMARKED
The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7 The question basically asks for the probability of choosing 1,2,6 or 7. = 8/15
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Manager
Joined: 25 Jun 2012
Posts: 65
Location: India
WE: General Management (Energy and Utilities)

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
08 Jan 2013, 22:47
MacFauz wrote: The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
The question basically asks for the probability of choosing 1,2,6 or 7.
= 8/15 Hi Can you please explain in detail? how u got the values of set?



VP
Joined: 02 Jul 2012
Posts: 1197
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
08 Jan 2013, 22:58
6
This post received KUDOS
bhavinshah5685 wrote: MacFauz wrote: The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
The question basically asks for the probability of choosing 1,2,6 or 7.
= 8/15 Hi Can you please explain in detail? how u got the values of set? Looking at the table., The column on the left shows the value of X and the column on the right shows the number of times the value appears. The question statement is just beating around the bush a lot to ask a simple question. What is the probability that 4  X > 1.5. For such a case, X has to be 1,2,6 or 7.
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Manager
Joined: 04 Oct 2011
Posts: 204
Location: India
Concentration: Entrepreneurship, International Business
GPA: 3

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
09 Jan 2013, 20:47
1
This post received KUDOS
MacFauz wrote: bhavinshah5685 wrote: MacFauz wrote: The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
The question basically asks for the probability of choosing 1,2,6 or 7.
= 8/15 Hi Can you please explain in detail? how u got the values of set? Looking at the table., The column on the left shows the value of X and the column on the right shows the number of times the value appears. The question statement is just beating around the bush a lot to ask a simple question. What is the probability that 4  X > 1.5. For such a case, X has to be 1,2,6 or 7. Hi MacFauz, I guess answer is correct but the solution seems to be different to me. Pls correct me! given absolute difference is \(4X >1.5\) so \(1.5> 4X >1.5\) solving this \(2.5 < X < 6.5\) This gives range from 3,3,3,4,5,5,5,6 Anyways, answer will be 8/15. Actually i did this wrong. On seeing ur solution i got it
_________________
GMAT  Practice, Patience, Persistence Kudos if u like



VP
Joined: 02 Jul 2012
Posts: 1197
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
09 Jan 2013, 21:27
shanmugamgsn wrote: MacFauz wrote: bhavinshah5685 wrote: The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
The question basically asks for the probability of choosing 1,2,6 or 7.
= 8/15
Hi Can you please explain in detail?
how u got the values of set? Looking at the table., The column on the left shows the value of X and the column on the right shows the number of times the value appears. The question statement is just beating around the bush a lot to ask a simple question. What is the probability that 4  X > 1.5. For such a case, X has to be 1,2,6 or 7. Hi MacFauz, I guess answer is correct but the solution seems to be different to me. Pls correct me! given absolute difference is \(4X >1.5\) so 1.5> 4X >1.5solving this \(2.5 < X < 6.5\) This gives range from 3,3,3,4,5,5,5,6 Anyways, answer will be 8/15. Actually i did this wrong. On seeing ur solution i got it The step in red is incorrect. You should note that the least value that 4X can take is 0. So, it can never be less than 1.5. The inequality should actually be X<2.5 or X>5.5.
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Manager
Joined: 04 Oct 2011
Posts: 204
Location: India
Concentration: Entrepreneurship, International Business
GPA: 3

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
09 Jan 2013, 22:53
Actually it should be 1.5> 4X >1.5 (it was a typo above) But still i didnt get u! 4X can be zero ? then 4X>1.5 will be 0>1.5This isnt wrong? Messed up Pls explain
_________________
GMAT  Practice, Patience, Persistence Kudos if u like



VP
Joined: 02 Jul 2012
Posts: 1197
Location: India
Concentration: Strategy
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
09 Jan 2013, 22:58
shanmugamgsn wrote: Actually it should be 1.5> 4X >1.5 (it was a typo above) But still i didnt get u! 4X can be zero ? then 4X>1.5 will be 0>1.5This isnt wrong? Messed up Pls explain I guess I wasn't clear. What I meant to say was that a modulus value cannot be negative. Of course in this question, we want only values for which 4X>1.5. The range that you have given (1.5> 4X >1.5) is not a valid one. A number cannot be both greater than 1.5 and lesser than 1.5. Rather the interval should be 1.5 < 4X OR 4X < 1.5
_________________
Did you find this post helpful?... Please let me know through the Kudos button.
Thanks To The Almighty  My GMAT Debrief
GMAT Reading Comprehension: 7 Most Common Passage Types



Manager
Joined: 04 Oct 2011
Posts: 204
Location: India
Concentration: Entrepreneurship, International Business
GPA: 3

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
10 Jan 2013, 20:05
MacFauz wrote: shanmugamgsn wrote: Actually it should be 1.5> 4X >1.5 (it was a typo above) But still i didnt get u! 4X can be zero ? then 4X>1.5 will be 0>1.5This isnt wrong? Messed up Pls explain I guess I wasn't clear. What I meant to say was that a modulus value cannot be negative. Of course in this question, we want only values for which 4X>1.5. The range that you have given (1.5> 4X >1.5) is not a valid one. A number cannot be both greater than 1.5 and lesser than 1.5. Rather the interval should be 1.5 < 4X OR 4X < 1.5 Thanks MacFauz... ya i got my mistake in Inequalities. Thanks dude...
_________________
GMAT  Practice, Patience, Persistence Kudos if u like



VP
Status: Far, far away!
Joined: 02 Sep 2012
Posts: 1101
Location: Italy
Concentration: Finance, Entrepreneurship
GPA: 3.8

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
29 Mar 2013, 00:51
2
This post received KUDOS
x has values between 1 and 7 so \(4x>\frac{3}{2}\)= 41=3>3/242=2>3/243=1>3/2 44=0>3/2 45=1>3/246=2>3/247=3>3/2The value that respect 4x>3/2 are 1,2,6,7 that have a frequency of 3,1,1,3 so \(3+1+1+3\) = total frequencies of "right" events, and this will be our numerator. Our denominator will be the tot number of combinations = \(3+1+3+1+3+1+3= 15.\) Answer \(\frac{8}{15}\)
_________________
It is beyond a doubt that all our knowledge that begins with experience.
Kant , Critique of Pure Reason Tips and tricks: Inequalities , Mixture  Review: MGMAT workshop Strategy: SmartGMAT v1.0  Questions: Verbal challenge SC III CR New SC set out !! , My QuantRules for Posting in the Verbal Forum  Rules for Posting in the Quant Forum[/size][/color][/b]



Intern
Joined: 18 Jul 2013
Posts: 1

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
18 Jul 2013, 03:44
I have a question regarding the denominator 15 : why do we take into consideration the value 4 since it occurs only once and we're looking for the the difference between this value and the others. I had the answer wrong because I assumed the denominator was 14  could someone try to explain?



Director
Joined: 29 Nov 2012
Posts: 828

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
18 Jul 2013, 07:50
aa81 wrote: I have a question regarding the denominator 15 : why do we take into consideration the value 4 since it occurs only once and we're looking for the the difference between this value and the others. I had the answer wrong because I assumed the denominator was 14  could someone try to explain? The question states What is the probability that the absolute value of the difference between the mean of the distribution which is 4 and a randomly chosen value of x will be greater than 3/2? you get 15 when you add the frequency ( 3+1+3 etc) The set is The set is 1,1,1,2,3,3,3,4,5,5,5,6,7,7,7
_________________
Click +1 Kudos if my post helped...
Amazing Free video explanation for all Quant questions from OG 13 and much more http://www.gmatquantum.com/og13th/
GMAT Prep software What if scenarios http://gmatclub.com/forum/gmatprepsoftwareanalysisandwhatifscenarios146146.html



Manager
Joined: 13 Dec 2012
Posts: 193

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
18 Jul 2013, 08:41
fozzzy wrote: X frequency 1 3 2 1 3 3 4 1 5 3 6 1 7 3
The variable x takes on integer values between 1 and 7 inclusive as shown above. What is the probability that the absolute value of the difference between the mean of the distribution which is 4 and a randomly chosen value of x will be greater than 3/2?
A) 8/15 B) 4/7 C) 4/5 D) 6/7 E) 8/7 How can the probability of doing something be 3/2? How can the probability of doing something be greater than 1? I don't understand what y'all are calculating.
_________________
Blog: The MBA Journey of an African Doctor
Blog updated: July 27, 2014



Director
Joined: 29 Nov 2012
Posts: 828

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
18 Jul 2013, 09:29
knightofdelta wrote: How can the probability of doing something be 3/2?
How can the probability of doing something be greater than 1?
I don't understand what y'all are calculating.
The final answer is below 1 8/15 = 0.5333
_________________
Click +1 Kudos if my post helped...
Amazing Free video explanation for all Quant questions from OG 13 and much more http://www.gmatquantum.com/og13th/
GMAT Prep software What if scenarios http://gmatclub.com/forum/gmatprepsoftwareanalysisandwhatifscenarios146146.html



Manager
Joined: 13 Dec 2012
Posts: 193

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
18 Jul 2013, 09:35
fozzzy wrote: knightofdelta wrote: How can the probability of doing something be 3/2?
How can the probability of doing something be greater than 1?
I don't understand what y'all are calculating.
The final answer is below 1 8/15 = 0.5333 Then the answer should be 0 since the answer will be below 3/2. 3/2 is higher than 1 and the answer is below 1. Therefore, since the answer is certainly below 1 and 1 is below 3/2, then the answer is 0. And 0 is not one of the answer choices. Summary: the question is faulty.
_________________
Blog: The MBA Journey of an African Doctor
Blog updated: July 27, 2014



Math Expert
Joined: 02 Sep 2009
Posts: 44566

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
21 Jul 2013, 02:41
knightofdelta wrote: fozzzy wrote: knightofdelta wrote: How can the probability of doing something be 3/2?
How can the probability of doing something be greater than 1?
I don't understand what y'all are calculating.
The final answer is below 1 8/15 = 0.5333 Then the answer should be 0 since the answer will be below 3/2. 3/2 is higher than 1 and the answer is below 1. Therefore, since the answer is certainly below 1 and 1 is below 3/2, then the answer is 0. And 0 is not one of the answer choices. Summary: the question is faulty. Please read the question carefully. The question asks "what is the probability that SOME VALUE will be greater than 3/2?" not "is the probability of SOME EVENT greater than 3/2?"
_________________
New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  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? Extrahard Quant Tests with Brilliant Analytics



Intern
Joined: 01 Apr 2014
Posts: 1

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
03 Sep 2015, 18:21
Hi,
Can someone explain why we have considered frequencies while the stem asks us about the value of X?
I mean, the probability of abs (4X) >1.5 , then what values of X can be considered ?
Or did i miss something?



NonHuman User
Joined: 09 Sep 2013
Posts: 6632

Re: The variable x takes on integer values between 1 and 7 inclusive as [#permalink]
Show Tags
02 Nov 2017, 08:54
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




Re: The variable x takes on integer values between 1 and 7 inclusive as
[#permalink]
02 Nov 2017, 08:54






