The following table gives the literacy rate (in percentage) in 40 cities. Find the mean literacy rate, choosing a suitable method.


Literacy rate (%)



45 - 55



55 - 65



65 - 75



75 - 85



85 - 95



Number of cities



4



11



12



9



4


We will solve this using direct method.


LITERACY RATE(%)



MID - POINT(xi)



NUMBER OF CITIES(fi)



fixi



45 - 55



50



4



200



55 - 65



60



11



660



65 - 75



70



12



840



75 - 85



80



9



720



85 - 95



90



4



360



TOTAL




40



2780



We have got


Σfi = 40 and Σfixi = 2780


∵ mean is given by



⇒


⇒


Thus, mean is 69.5%.


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