Question

31.Calculate the arithmetic mean from the data given below by using short-cut method: (6) Marks Frequency 0-10 2 10-20 2 20-30 10 30-40 15 40-50 7 50-60 4​

Answer 1

Answer:

MarksClass−Mark

xi No.ofstudents

fi fixi 10.5−20.5 15.5 2 31 20.5−30.5 25.5 6 153 30.5−40.5 35.5 10 355 40.5−50.5 45.5 12 546 50.5−60.5 55.5 9 499.5 60.5−70.5 65.5 7 458.5 70.5−80.5 75.5 4 302   ∑fi=50 ∑fixi=2345 ⇒  Mean(x)=∑fi∑fixi=502345