The table below shows the daily expenditure on food of 25 households in a locality.


Daily expenditure (in Rs):



100-150



150-200



200-250



250-300



300-350



Number of households:



4



5



12



2



2


We may calculate class marks (xi) for each interval by using the relation

xi =


Class size = 50


Now taking 225 as assumed mean we can calculate as follows:


Daily expenditure (In Rs)



fi



di = xi – A = xi - 225



ui =



xi



fiui



100-150



4



-100



-2



125



-8



150-200



5



-50



-1



175



-5



200-250



12



0



0



225



0



250-300



2



50



1



275



2



300-350



2



100



2



325



4




N = 25






∑fiui = -7



Mean (x̅) = A + * h


= 225 + * 50


= 225 – 14 = 211


So mean expenditure on food is 211


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