During the medical check-up of 35 students of a class, their weights were recorded as follows:


Weight (in kg)



Number of students



Less than 38


Less than 40


Less than 42


Less than 44


Less than 46


Less than 48


Less than 50


Less than 52



0


3


5


9


14


28


32


35



Draw a less than type ogive for the given data. Hence obtain the median weight from the graph and verify the result by using the formula


The frequency distribution table of less than type graph is as follows:


Weight (in kg)


Upper class limits



No. of students


(Cumulative Frequency)



Less than 38


Less than 40


Less than 42


Less than 44


Less than 46


Less than 48


Less than 50


Less than 52



0


3


5


9


14


28


32


35




Now,


Taking upper class interval on x-axis and their respective frequencies on y-axis, ogive will be:



Here, N = 35



Mark the point A whose ordinate is 17.5 and is x-ordinate is 46.5.


Hence,


Median of the data is 46.5


Now,


It can be observed that the difference between two consecutive upper class limits is 2


The class marks with respective frequencies are obtained below:


Weight (in kg)



frequency



Cumulative Frrequency



Less than 38



0



0



38-40



3



3



40-42



2



5



42-44



4



9



44-46



5



14



46-48



14



28



48-50



4



32



50-52



3



35



N



35




We can see that the cumulative frequency is greater than n/2 and is 28 which belongs to the interval 46-48


Hence,


Median class = 46-48


Lower limit, l = 46


cf = 14


f = 14


h = 2


Now,


Median can be calculated as:





= 46.5


2
1