Question

The following distribution shows the daily pocket allowance of children of a locality. The assumed mean pocket allowance is 18. Find the missing frequency f:

Daily pocket
11-1313-15 15–17 17-19 19–21 | 21-23 23—25
allowance (in)
Number of children
7
6
9
13
f
5
4​

Answer 1

Answer:

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Step-by-step explanation:

ui=xi−ah=dih

di=xi−a

assumed mean=a=18

h=13−11=2

acc to series

xi=12,14,16,18,20,22,24

fi=7,6,9,13,f,5,4

di=−6,−4,−2,0,2,4,6

ui=−3,−2,−1,0,1,2,3

fiui=−21,−12,−9,0,f,10,12

∑fi=44−f

∑fiui=f−2o

mean=a+(∑fiui∑fi)h

18=18+(f−2044+f)⋅2

f−2044+f=0

f−20=0

f=20