Find out the arithmetic mean by the Step-deviation Method of the following: {:("Class Interval",0-10,10-20,20-30,30-40,40-50,50-60,60-70,70-80),("Frequency "," "12," "16," "32," "52," "42," "32," "18," "12):}

Find out the arithmetic mean by the Step-deviation Method of the follo

1.	Find out the arithmetic mean by the Step-deviation Method of the following: {:("Class Interval",0-10,10-20,20-30,30-40,40-50,50-60,60-70,70-80),("Frequency "," "12," "16," "32," "52," "42," "32," "18," "12):}
Answer» Solution : `barX=A+(sumfd')/(sumf) xx C` `= 45+(-108)/(216) xx 10` =45 - 5 = 40 ARITHMETIC Mean = 40.