BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

median

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 109
Joined: Wed Feb 15, 2012 7:09 am
Thanked: 8 times
Followed by:2 members

median

by ankita1709 » Sat Jun 02, 2012 7:37 am
If set S consists of even number of integers, is the median of set negative?
1.Exactly half of all elements of set S are positive.
2.The largest negative element of set S is -1.
Top
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Sat Jun 02, 2012 7:49 am
ankita1709 wrote:If set S consists of even number of integers, is the median of set negative?
1.Exactly half of all elements of set S are positive.
2.The largest negative element of set S is -1.
Note that, -1 is the largest negative integer. Hence, statement 2 is a redundant information. Therefore, the answer is either A or E.

Now for statement 1,

Statement 1: The median may be negative or zero or positive. For example,
  • 1. {-1, 0, 1, 2} --> Median = (0 + 1)/2 = 0.5 > 0
    2. {-1, 1} --> Median = (-1 + 1)/2 = 0
    3. {-3, -1, 1, 2} --> Median = (-2 + 1)/2 = -0.5 < 0
Not Sufficient

The correct answer is E.
Last edited by Anurag@Gurome on Sun Jun 03, 2012 9:02 pm, edited 1 time in total.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Junior | Next Rank: 30 Posts
Posts: 21
Joined: Sun Aug 01, 2010 11:22 am

by khandelwal.ab » Sun Jun 03, 2012 11:17 am
Anurag,

I am unable to understand your explanation, you have quoted the below examples to depict the various scenarios:


1. {-1, 0, 1, 2} --> Median = (-1 + 0 + 1 + 2)/2 = 1 > 0
2. {-1, 1} --> Median = (-1 + 1)/2 = 0
3. {-3, -1, 1, 2} --> Median = (-3 -2 + 1 + 2)/2 = -1 < 0


But I don't understand the above calculations of median...

Shouldn't {-1, 0, 1, 2}'s median be (0+1)/2??

Not sure if I am missing something here..
Top
User avatar
Legendary Member
Posts: 520
Joined: Sat Apr 28, 2012 9:12 pm
Thanked: 339 times
Followed by:49 members
GMAT Score:770

by eagleeye » Sun Jun 03, 2012 11:27 am
khandelwal.ab:

Anurag made a mistake while he might have been trying to do it quickly. I am sure this is what he wanted to write:

1. {-1, 0, 1, 2} --> Median = (0 + 1)/2 = 1/2 > 0
2. {-1, 1} --> Median = (-1 + 1)/2 = 0
3. {-3, -1, 1, 2} --> Median = (-2 + 1)/2 = -1/2 < 0

The median value is the value smack in the middle of numbers arranged in an increasing or decreasing order. For even number of elements, you average the middle two; for odd number of elements, you take the middle value. I am sure you knew this already, but I wanted to clear any confusion.

Anurag, could you please edit your post?

Let me know if this helps :)
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 123
Joined: Fri Apr 20, 2012 4:36 am
Thanked: 29 times
Followed by:1 members

by Ashujain » Mon Jun 04, 2012 3:56 am
ankita1709 wrote:If set S consists of even number of integers, is the median of set negative?
1.Exactly half of all elements of set S are positive.
2.The largest negative element of set S is -1.
St1) Insufficient because we do not the value of the middle two terms (we just know that one is positive and one is negative) which is required for the calculation of median when even number of integers are there in a set

St2) Insufficient: Same reason as above

Combine st1 and st2: Now we know that one of the middle terms is -1 and the other middle term has to be > or = 1 (because half are positive integers) and therefore, the median will be > or = 0.

Hence, C
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Mon Jun 04, 2012 5:52 am
Edited the reply.
Thanks eagleeye.
Ashujain wrote:...Now we know that one of the middle terms is -1..
Not necessarily.
See my examples.
The key is "Exactly half of all elements of set S are positive" does not necessarily mean the rest half is negative.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Senior | Next Rank: 100 Posts
Posts: 46
Joined: Sun Jul 17, 2011 2:58 am
Thanked: 1 times

by aditya.j » Wed Jun 13, 2012 11:28 pm
Note that, -1 is the largest negative integer. Hence, statement 2 is a redundant information. Therefore, the answer is either A or E.

I didnt quite get why -1 is redundant..
Top
Junior | Next Rank: 30 Posts
Posts: 17
Joined: Sun Apr 22, 2012 11:22 am

by jrakhe » Thu Jun 14, 2012 6:19 pm
I am also not sure why -1 is redundant.. :(

According me answer should be B
Top
Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Sat Jun 16, 2012 10:28 pm

by windchaser » Sat Jul 07, 2012 6:58 pm
If set S consists of even number of integers, is the median of set negative?
1.Exactly half of all elements of set S are positive.
2.The largest negative element of set S is -1.

1) obviously insufficient, don't have any numbers to work with
2) the largest NEGATIVE element of the set is -1, that means it could be {-1,3,4,5} or {-3,-2,-1,1}, obviously insufficient, because the statement never said anything about how many positive or negative integers are there

if we combine both, the set could be {-1,0,0,1,3,4}, in this case, the median is 0.5
the set could also be {-3,-2,-1,1,3,4}, in this case the median is 0
so the median has to be >0, therefore, we can conclude that the median of the set will not be negative, that's why I think it should be C
Top
Post new topic Post Reply
• Page 1 of 1