The following are the probability distribution of the discrete random variable. Calculate the cumulative discrete function.
a) 0.2, 0.4, 0.6, 0.8, 1.0
b) 0.1, 0.3, 0.5, 0.7, 0.9
c) 0.4, 0.6, 0.8, 1.0, 1.2
d) 0.3, 0.6, 0.9, 1.2, 1.5