If the mean of the following distribution is 27, find the value of p.


Class:



0-10



10-20



20-30



30-40



40-50



Frequency:



8



p



12



13



10



Class interval



Mid value (xi)



Frequency (fi)



fixi



0-10



5



8



40



10-20



15



p



15p



20-30



25



12



300



30-40



35



13



455



40-50



45



10



450





N = 43 + p



∑fixi = 1245 + 15p



Given, mean =


27 =


1161 + 27p = 1245 + 15p


27p – 15p = 1245 – 1161


12p = 84


p = 7


20