Question

Find the arithmetic mean from following data

Mark : 10-20 20-30 30-40 40-50 50-60

No of student : 6 12 18 10 4

Answer 1

let the mean be x.
x=10 + 20.+ 20.+ 30. + 30. +40. + 40. + 50.+ 50. + 60/5
x=350/5
x=70.