B.1) Let the random variable X represent the number of automobiles that are used for official business purposes on any given workday. The probability distribution for company A is
x: 1, 2, 3
pA(x): 0.3, 0.4, 0.3
and for company B is
x: 0, 1, 2, 3, 4
pB(x): 0.2, 0.1, 0.3, 0.3, 0.1
Compute the variances for both companies, and compare them.
B.2) The percentage of impurities per batch in a certain type of industrial chemical is a random variable X having the probability density function
f(x) = {12x^2 (1 - x); 0 ≤ x ≤ 1
0; otherwise
a) Suppose a batch with more than 40% impurities cannot be sold. What is the probability that a randomly selected batch will not be sold?
b) Suppose the dollar value of each batch is given by V=5-0.5X. Find the expected value and variance of V.