Calculate the mean of the distribution given below using the short cut method
Marks11−2021−3031−4041−5051−6061−7071−80No. of students261012974
Let A=45.5
MarksNumber ofMid−valuedi=xi−Afidistudents(fi)(xi)11−20215.5−30−6021−30625.5−20−12031−401035.5−10−10041−5012A=45.50051−60955.5109061−70765.52014071−80475.530120Total∑fi=50∑fidi=70
Mean (¯x)=A+∑fidI∑fi
=45.5+7050=45.5+1.4=46.9