Question

If total frequencies of three series are 50, 60
and 90 and their means are 12, 15 and 20
respectively, then
the mean
mean of their
composite series is
b) 15.5 c) 16.5 d) 14.5
a) 16​

Answer 1

Answer:

c

Step-by-step explanation:

50×12 + 60×15 + 90×20 /(50+60+90)

= 3300/200 = 16.5