A life insurance agent found the following data for distribution of ages of 100 policy holders. Calculate the median age, if policies are only given to persons having age 18 years onwards but less than 60 years.


Age in years



Number of policy holders



Blow 20



2



Blow 25



6



Blow 30



24



Blow 35



45



Blow 40



78



Blow 45



89



Blow 50



92



Blow 55



98



Blow 60



100



: Here class width is not same. There is no need to adjust the frequencies according to class intervals. Now given frequency table is of less than type represented with upper class limits. As policies were given only to persons having age 18 years onwards but less than 60 years we can define class intervals with their respective cumulative frequencies as below:


Age (in years)



No. of policy holders



Cumulative frequency



18-20



2



2



20-25



6 - 2 = 4



6



25-30



24 - 6 = 18



24



30-35



45 - 24 = 21



45



35-40



78 – 45 = 33



78



40-45



89 – 78 = 11



89



45-50



92 – 89 = 3



92



50-55



98 – 92 = 6



98



55-60



100 – 98 = 2



100



Now from the table we may observe that N = 100


Cumulative frequency just greater than (N = 50) is 78belonging to interval 35-40.


So, Median Class = 35 – 40


Lower limit (l) = 35


Class size (h) = 5


Frequency (f) = 33 and F = 45


Median = l + * h


= 35 + () * 5


= 35 + * 5


= 35 + 0.76


= 35.76


So, Median age is 35.76 years.


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