An automobile service facility specializing in engine tuneup

An automobile service facility specializing in engine tune-ups knows that 50% of all tune-ups are done on four-cylinder automobiles, 40% on six-cylinder automobiles, and 10% on eight-cylinder automobiles. Let X= the number of cylinders on the next car to be tuned. What is the pmf of A? Calculate the expected value of the number of cylinders on the next car to be tuned.

Solution

Solution :

( a ) The pmf of X is :

x	4	6	8
P(x)	0.50	0.40	0.10