Q10 of 69 Page 7

Find the median life time of a lamp. 10. The frequency distribution of the number of letters in the English alphabets in the names of 100 students is as given below:


Determine the median numbers of letters in the names.


We have n = 100


So,


The cumulative Frequency just greater than is 62 then the median class is 15.5 – 20.5 such that


the lower limit (l) = 15.5


cumulative frequency of the class preceding 15.5-20.5 (cf) = 30


frequency of the median class 15.5 – 20.5 = 32,


class size (h) = 5


Using the formula,, we have




= 15.5 + 3.125


= 18.625 = 18.63


So, the median numbers of letters in the names is 18.63


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