Question

Marks in Statistics of the students of Class XI are given below.
Find out arithmetic mean.
`{:("Marks",,"Number of Students"),("Less than 10",," "5),("Less than 20",," "17),("Less than 30",," "31),("Less than 40",," "41),("Less than 50",," "49):}`

Answer 1

A Cumulative Frequency Distribution should first be converted into a Simple Frequency Distribution, as under:

Now, mean value of the data is obtained using Direct Method as under:

`barX=(sumfm)/(sumf)=(1,265)/49=25.82`
Arithmetic Mean = 25.82 marks.