A doctor's office has four telephone lines, each of which can be independently dialed by any patient. Assume that, on any given business day, the probability that the first call is received on line 1, 2, 3, and 4 are 0.2, 0.3, 0.2, and 0.3, respectively. And the first calls are independent from one business day to the other. For n business days, let Y be the number of days on which the first call arrives on line i, i=1,2,3,4.
i. (2 pts) What is the distribution for the random vector (Y1, Y2, Y3, Y4)? Write the name of the distribution with its parameters.
ii. (2 pts) What is the distribution for the random variable Y4? Write the name of the distribution with its parameters.
iii. (4 pts) Let n=10, find P(Y1=2, Y2=4, Y3=2)
iv. (4 pts) Let n=8, write the expression for P(Y3=Y4)
v. (4 pts) Let n=10. Given that Y4=2, compute the probability that Y1=2, Y2=4, Y3=2