Discrete Random Variables


Exercises for students
Solve the following problems on paper and check your working using the above applet:

The random variable X takes value 1, 2, 3, 4, 5 with probabilities 1/9, 1/9, 2/9, 2/9, p respectively. Find p.

The random variable X takes value 1, 2, 3 with probabilities 1/4, 1/2, 1/4 respectively. Find

P(X <= 2)

E(X), E(X²) & Var(X)

E(2X + 3) & Var(2X + 3)

E(3X) & Var(3X)

E(-3X) & Var(-3X)

The random variable X takes value -1, 0, 1 with probabilities 1/4, 1/2, 1/4 respectively.
State E(X).
Find Var(X).

The no. of days of medical leave, X, of a randomly chosen employee in a company in a year can be modelled by the following discrete probability distribution:

No. of days, x	0	1	2	3
P(X=x)	0.3	0.5	0.1	0.1

Calculate E(X) & Var(X).

Right-click here to download this page and the Java Class File.