Discuss the following:
A grocery chain wants to taste-test a private label cola drink. A tester is given eight unmarked glasses, four containing the private-label drink and four containing a nationally advertised cola. The tester is asked to identify the four glasses containing the private-label drink. How many different choices of four glasses can the taster make?
Phone calls for information arrive at an operator switchboard at an average rate of two calls per minute. Assume that the number of calls in any time interval is a Poisson random variable.
a. What is the probability of exactly five calls in the next three minutes?
b. What is the probability that the operator will receive at least one phone call for information in the next three minutes?