Calculate the Mean of the given distribution, using Assumed mean Method.
MarksNo. of Students10−20220−30630−401040−501250−60960−70870−80480−903
ClassesClass marks (x)d=x−aFrequency (f)fd10−2015−402−8020−3025−306−18030−4035−2010−20040−5045−1012−12050−605509060−70651088070−80752048080−908530390∑d=−40∑f=54∑fd=330
Let, the assumed mean 'a' = 55
∴Mean =a+∑fd∑f
=55+−33054=55−6.11=48.89