Example The mean weight of 98 students is
found to be 50 lbs. It is later discovered that the frequency of
the class interval (30- 40) was wrongly taken as 8 instead of 10.
Calculate the correct mean.
Note that the class-mark of class interval (30 - 40) is 35 and for the calculation of the mean we consider class marks.
Also the correct
Therefore, the correct mean
Example The sum of the deviations of 'n'
observation values of a variate from a
constant 'a', is S. Show that the arithmetic mean is .
Dividing by n to get the mean