Question

the mean of following disterbution is 31.4 .find the missing frequency'x'.class interval .0-10,10-20,20-30,30-40,40-50,50-60. frequency 5,x,10,12,7,8.

Answer 1

your answer is this x =30.56

Answer 2

soln
x. f. fx
0-10. 5. 25
10-20. x. 15x
20-30. 10. 250
30-40 12. 420
40-50 7. 315
50-60 8. 440

mean=£fx/£f
25+15x+250+420+315+440/5+x+22+15
1450+15x/42+x=31.4
1450+15x=1318.8+31.4x
131.2=16.4x
x=8