For the following data, mean of x is found to be 7.3. The missing frequency is
x : 5 6 7 8 9
f : 4 6 12 - 8
10
Mean=5×4 + 6×6 + 7×12 + 8×f + 9×84 + 6 + 12 + f + 8
Where f is the missing frequency
⇒7.3=20 + 36 + 84 + 8f + 7230 + f=212+8f30+f⇒219+7.3f=218+8f⇒7=.7f⇒f=7.7=707=10