Median problem

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Median problem

by nisha.menon294 » Sat Apr 17, 2010 3:58 am
In which class interval does the median score of the 73 students that appeared for an exam co - incise with ?

scores obtained ----------------- No: of students
50-59 ------------------ 2
60-69 ------------------ 10
70-79 ------------------ 12
80-89 ------------------ 27
90-99 ------------------ 21

Options
a)60-60
b)70-79
c)80-89
d)cannot be determined
Source: — Problem Solving |

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by sanju09 » Sat Apr 17, 2010 4:21 am
nisha.menon294 wrote:In which class interval does the median score of the 73 students that appeared for an exam co - incise with ?

scores obtained ----------------- No: of students___cumulative frequency
50-59 ------------------ 2___2
60-69 ------------------ 10___12
70-79 ------------------ 12___24
80-89 ------------------ 27___51
90-99 ------------------ 21___72

Options
a)60-60
b)70-79
c)80-89
d)cannot be determined
This is not a GMAT query.

Never mind.

Prepare the cumulative frequency table, see in red above

Median of 72 items in arranged order is 36th and 37th items, each lie in the [spoiler]80-89[/spoiler] class interval.

[spoiler]C[/spoiler]
The mind is everything. What you think you become. -Lord Buddha



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by nisha.menon294 » Sat Apr 17, 2010 4:25 am
Thanks , this was another question in gmat prep test ...

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by ironstar37 » Tue Apr 20, 2010 10:21 am
An easy way to think about this is to add up the no of students and compare numbers to both extremes of the scores.
2+10+12 = 24, therefore if the 90-99 category only has 21 students, the median will have to be in 80-89 category

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by harshavardhanc » Tue Apr 20, 2010 11:32 am
nisha.menon294 wrote:In which class interval does the median score of the 73 students that appeared for an exam co - incise with ?

scores obtained ----------------- No: of students
50-59 ------------------ 2
60-69 ------------------ 10
70-79 ------------------ 12
80-89 ------------------ 27
90-99 ------------------ 21

Options
a)60-60
b)70-79
c)80-89
d)cannot be determined
GMAC can make a problem so difficult! Isn't it? ;)

they have arranged the numbers for us and are just asking which number will be the median?

total number of observations is 73, so the median will be 37th number which will fall in the interval 80-89 .

(2+10+12+13)
Regards,
Harsha

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by sanju09 » Wed Apr 21, 2010 2:57 am
harshavardhanc wrote:
nisha.menon294 wrote:In which class interval does the median score of the 73 students that appeared for an exam co - incise with ?

scores obtained ----------------- No: of students
50-59 ------------------ 2
60-69 ------------------ 10
70-79 ------------------ 12
80-89 ------------------ 27
90-99 ------------------ 21

Options
a)60-60
b)70-79
c)80-89
d)cannot be determined
GMAC can make a problem so difficult! Isn't it? ;)

they have arranged the numbers for us and are just asking which number will be the median?

total number of observations is 73, so the median will be 37th number which will fall in the interval 80-89 .

(2+10+12+13)
stem says it's 73; but I worked on the presented data thereafter
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com