Question

Airlines sometimes overbook flights. Suppose that for a plane with 50 seats, 55 passengers have tickets. Define the random variable Y as the number of ticketed passengers who actually show up for the flight. The probability mass function of Y appears in the accompanying table.

y	45	46	47	48	49	50	51	52	53	54	55
p(y)	0.02	0.10	0.12	0.14	0.25	0.17	0.01	0.05	0.06	0.05	0.03

Calculate

V(Y)

and

σ_Y

Determine the probability that Y is within 1 standard deviation of its mean value.

Answer 1

TOPIC: Mean and variance of a discrete random variable.