Find the missing frequency (p) for the following distribution whose mean is 7.68.


x:



3



5



7



9



11



13



f :



6



8



15



p



8



4



x



f



fx



3



6



18



5



8



40



7



15



105



9



P



9P



11



8



88



13



4



52




N = P + 41



∑fx = 9P + 303



Given, mean = 7.68


= 7.68


= 7.68



9P – 7.68P = 314.88 – 303


1.32P = 11.88


P =


P = 9


7