Median problem from GMAT PREP. Plz help.

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 19
Joined: Thu Jul 17, 2008 9:05 pm
Thanked: 2 times

Median problem from GMAT PREP. Plz help.

by ok24by7 » Sun Aug 31, 2008 10:26 am
How to solve this attached problem?
Attch added again..............

Thanks.
Attachments
New Microsoft Word Document.doc
(50.5 KiB) Downloaded 279 times
Last edited by ok24by7 on Sun Aug 31, 2008 10:40 am, edited 1 time in total.

Legendary Member
Posts: 829
Joined: Mon Jul 07, 2008 10:09 pm
Location: INDIA
Thanked: 84 times
Followed by:3 members
ok24by7 wrote:How to solve this attached problem?

Thanks.
i dont see any attachment . did u forget to add the attachment?

Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Tue Aug 26, 2008 10:22 am

by Mpalmer22 » Fri Sep 05, 2008 1:09 pm
Think of the median as the middle number not as the average. The question is phrased difficultly in that it seems like it is telling you the median number is 73.

For example the median of this set of numbers:
1,2,3,4,4,4,4 is 4 b/c it is in the middle of the set.
However, if the set was:
1,2,3,4,4,4 is 3.5 b/c when you have an even number in the data set, you average the middle 2 numbers to get the median.

The problem you posted is a little tricky since it seems like the median would be closer to the average, but it is the middle number instead. I like to cross a numbers off of each end until if find the middle, and by doing that you see that the majority of the numbers are concentrated to the higher end.

Let me know if you need any more help on that.

Newbie | Next Rank: 10 Posts
Posts: 3
Joined: Thu Jul 24, 2008 2:35 pm

by sg4931 » Mon Sep 08, 2008 3:10 pm
There are 73 individual scores in total. Call them -- S1, S2,S3........S73.

Rewrite the score table as follows:
50 - 59 : S1, S2
60 - 69 : S3, S4,..,S12
70 - 79 : S13,S14,...S28
80 - 89 : S29, S30,...S37,...S55

The median score is S37 (37th score is the mid point of 73 scores)

Looking at the table above, 37th score falls in the 80 - 89 interval

This how i have understood it. A tricky question indeed!

Newbie | Next Rank: 10 Posts
Posts: 2
Joined: Tue Sep 09, 2008 7:30 am

by kaur21 » Tue Sep 09, 2008 9:22 am
Fundamentally, this question will be solved by calculating cumulative frequency.

Senior | Next Rank: 100 Posts
Posts: 31
Joined: Mon Sep 15, 2008 6:16 pm
Thanked: 3 times

by dally_gmat » Thu Sep 18, 2008 7:43 pm
I lay my cards on same explanation as given below..

sg4931 wrote:There are 73 individual scores in total. Call them -- S1, S2,S3........S73.

Rewrite the score table as follows:
50 - 59 : S1, S2
60 - 69 : S3, S4,..,S12
70 - 79 : S13,S14,...S28
80 - 89 : S29, S30,...S37,...S55

The median score is S37 (37th score is the mid point of 73 scores)

Looking at the table above, 37th score falls in the 80 - 89 interval

This how i have understood it. A tricky question indeed!

Senior | Next Rank: 100 Posts
Posts: 31
Joined: Tue Sep 16, 2008 8:29 am
Location: Brazil
GMAT Score:460

time

by robzoc » Tue Sep 23, 2008 8:38 am
some times ( like this one) i believe that it´s better to number all the scores like:

1 for 50-59
2 for 60-69
3 for 70-79
4 for 80-89
5 for 90-99

of course in the heat of the moment this will be something like (1,2,3,4,5)

112222222222333333333333333444444444444444444444444444444444444444444444555555555555555555555555


count 37 digits and you will find the right interval !

Master | Next Rank: 500 Posts
Posts: 152
Joined: Wed Mar 12, 2008 4:36 pm
Thanked: 8 times
Followed by:2 members

simplify

by artistocrat » Mon Oct 06, 2008 3:26 pm
Easiest solution. How many scores? 73. The median will be the 37th value. (36 below and 36 above). The 37th value is in the 4th score interval, 80-89.

Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Fri Sep 19, 2008 10:50 am

by nicks » Sun Oct 12, 2008 9:45 pm
How I solved it:

Add up total number of scores and divide by 2 (73/2 = 36.5)

Which one has the 36.5th number in it?

50-59 has numbers 1-2
60-69 has numbers 3-12
70-79 has numbers 13-28
80-89 has numbers 29-55
90-99 has numbers 56-73

29 < 36.5 < 55