Find the mean of the data given in the table using step - deviation method.
Class IntervalFrequency0−101010−201220−30730−40640−50550−608
Class InternalMid value(xi)Frequency(fi)u=xi−ahfiui0−10510−3−3010−201512−2−2420−30257−1−730−4035=a60040−504551550−60558216Total∑ fi=48∑u=−3∑ fiui=−40
Let the assumed mean (a) = 35.
Class width (h) = 10 - 0 = 10
∴Mean=a+∑fiui∑fi×h
=35+−4048×10
=35+(−8.33)
=35−8.33
=26.67