Question

In the following frequency distribution, the frequency of the class interval (40-50) is not known. Find it, if the arithmetic mean of the distribution is 52.
`{:("Wages(Rs.)",10-20,20-30,30-40,40-50,50-60,60-70,70-80),("Number of Workes"," "5," "3," "4," "?," "2," "6," "13):}`

Answer 1

`barX=(sumfm)/(sumf)`
`52=(1,765+45f)/(33+f)`
`Or, 52(33+f)=1,765+34f`
`1,716+52f=1,765+45f`
`52f-45f=1,765-1,716`
`rArr" "7f=49`
`rArr" "f=7`
Missing Frequency =7.