Question

find the missing frequencies f1and f2,if mean of 50 observations given below is 36.4​

Answer 1

Answer:

It is given that Mean is 38.2

mean = \frac{\Sigma xifi}{\Sigma fi} \\ \\ 38.2 = \frac{1195 + 25f1 + 45f2}{50} \\ \\ 1910 = 1195 + 25f1 + 45f2 \\ \\ 715 = 25f1 + 45f2 \\ \\ 5f1 + 9f2 = 143 \: \: \: \: \: eq1 \\ \\ 31 + f1 + f2 = 50 \\ \\ f1 + f2 = 19 \: \: \: \: eq2 \\ \\

now solve eq1 and eq2 to find the value of f1 and f2

5f1 + 9f2 = 143 \\ \\ 5f1 + 5f2 = 95 \\ \\ - \: \: \: \: \: \: - \: \: \: \: \: - \\ \\ 4f2 = 48 \\ \\ f2 = 12 \\ \\ f1 + 12 = 19 \\ \\ f1 = 7 \\ \\

Thus, f1 =7

f2= 12

Hope it helps you.