Question

5. The mean of the following distribution is 52.Find x(3 marks)
30-40
40-50
Classes 10-20
Frequency 5
20-30
3
50-60
2
60-70
6
70-80
13
х
7​

Answer 1

Answer:

$mean(xi) = \frac{\Sigma \: fixi }{\Sigma \: fi } \\ 52 = \frac{1730 + 65x}{36 + x } \\ 52(1730 + 65x) = 36 + x \\ 89960 + 3380x = 36 + x \\ 89960 - 36 = x - 3380x \\ 89924 = - 3379x \\ - x = \frac{89924}{3379 } \\ - x = 26.6126073 \\ x = - 26.6126073$

see above photo for clarification