A hint to get started
Normalize a symmetric law and average an absolute distance
The discrete random variable has probability function
where . (i) Show that and state . (ii) Find . (iii) Find .
[2006/IJC/II/23]
CJC · Lecture · Example 12
Normalize the five masses, then use symmetry for the mean.
Average the absolute distances with their original probabilities.
Find the second moment before subtracting the squared mean.