A certain delivery service offers both express and standard delivery. Seventy-five percent of parcels are sent by standard delivery, and 25% are sent by express. Of those sent standard, 80% arrive the next day, and of those sent express, 95% arrive the next day. A record of a parcel delivery is chosen at random from the company’s files.
a. What is the probability that the parcel was shipped express and arrived the next day?
b. What is the probability that it arrived the next day?
c. Given that the package arrived the next day, what is the probability that it was sent express?
Let E denote the event that a parcel is sent express (so 
denotes the event that a parcel is sent standard), and let N denote the event that a parcel arrives the next day. Then P(E) = 0.25, P(N|E) = 0.95, and 
= 0.80).
(a) P(E ? N) = P(E)P(N|E) = (0.25)(0.95) = 0.2375.
(b) P(N)=P(N|E)P(E) + 
=(0.95)(0.25) + (0.80)(1 ? 0.25)
=0.8375
(c)
You might also like to view...
Equation 14.73, shown below, accounts for system pressures that are different from the reference pressure. Which of the following correctly describes the derivation of the equation?
A. Ideal gas behavior is assumed for the system
B. The effect of pressure was quantified using Poynting correction
C. The Peng Robinson equation of state was used to calculate fugacity
D. The effect of pressure was quantified using Raoult’s Law
E. None of these
____________________ is the amount of force applied and the distance over which it was applied.
Fill in the blank(s) with the appropriate word(s).
Connecting an ohmmeter to a live circuit usually results in damage to the meter.
Answer the following statement true (T) or false (F)
The amount of concrete slump is measured to the nearest _____
a. 1/2 inch b. 3/8 inch c. 1/4 inch d. 1/8 inch