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):}

Marks in Statistics of the students of Class XI are given below. Find

1.	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» Solution :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.