Wrong Number. A classic study by F. Thorndike on the number of calls to a wrong number appeared in the paper “Applications of Poisson’s Probability Summation” (Bell Systems Technical Journal, Vol. 5, pp. 604–624). The study examined the number of calls to a wrong number from coin-box telephones in a large transportation terminal. According to the paper, the number of calls to a wrong number, X, in a 1-minute period has a Poisson distribution with parameter λ = 1.75. Determine the probability that during a 1-minute period the number of calls to a wrong number will be

a. exactly two.

b. between four and six, inclusive.

c. at least one.