It is currently 18 Nov 2017, 18:30

### 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

# For a certain set of N numbers where N>1 is the average (ari

Author Message
Manager
Joined: 17 Sep 2011
Posts: 191

Kudos [?]: 140 [0], given: 8

For a certain set of N numbers where N>1 is the average (ari [#permalink]

### Show Tags

31 Jan 2012, 09:31
2
This post was
BOOKMARKED
For a certain set of N numbers where N>1 is the average (arithmetic mean ) equal to the median ?

1)If the N numbers in the set are listed in increasing order then the difference between any pair of successive numbers in the set is 2.

2)The range of the N numbers in the set is 2(N-1).

The answer is A. I know 2 is insufficient. My understanding of the statement A is as difference is 2 they are consecutive even nos so irrespective of whether N is odd or even and N>1 (for N=10 or 11 ) the average alwalys equals the median for consecutive even nos.

Is my understanding correct ? Could someone confirm ? The actual explanation given in the book for statement 1 is bit confusing. That's why I want someone to confirm.
_________________

_________________
Giving +1 kudos is a better way of saying 'Thank You'.

Kudos [?]: 140 [0], given: 8

Magoosh GMAT Instructor
Joined: 28 Dec 2011
Posts: 4488

Kudos [?]: 8737 [1], given: 105

Re: For a certain set of N numbers where N>1 is the average (ari [#permalink]

### Show Tags

31 Jan 2012, 15:03
1
KUDOS
Expert's post

You're perfectly right about Statement #2 -- it's not only insufficient --- it's completely useless.

Statement #1 says that the numbers are evenly-spaced, separated by steps of length 2.

They could be all evens: 6, 8, 10, 12, 14, . . . .

Or, they could be all odds: 5, 7, 9, 11, 13, . . . .

And actually, it doesn't matter. Here's a really easy rule-of-thumb to remember: on any list where all the numbers are even-spaced, the mean equals the median. Period. Starting point doesn't matter. Size of the space between the numbers doesn't matter. Even-spacing ---> mean = median.

The reason is: the mean always equals the median when the data is symmetric, and when each step is identical, then the whole set has mirror symmetry (imagine them as evenly-spaced dots on a number line).

Does that make sense? If you have any further question, please do no hesitate to ask.

Mike
_________________

Mike McGarry
Magoosh Test Prep

Education is not the filling of a pail, but the lighting of a fire. — William Butler Yeats (1865 – 1939)

Kudos [?]: 8737 [1], given: 105

Manager
Joined: 17 Sep 2011
Posts: 191

Kudos [?]: 140 [0], given: 8

Re: For a certain set of N numbers where N>1 is the average (ari [#permalink]

### Show Tags

01 Feb 2012, 01:13
Thanks a lot Mike for the reply. Yeah it was useful.
_________________

_________________
Giving +1 kudos is a better way of saying 'Thank You'.

Kudos [?]: 140 [0], given: 8

Re: For a certain set of N numbers where N>1 is the average (ari   [#permalink] 01 Feb 2012, 01:13
Display posts from previous: Sort by

# For a certain set of N numbers where N>1 is the average (ari

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne 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®.