Final answer:
a) The Poisson probability function is P(x; λ) = (e^-λ * λ^x) / x!. b) The expected number of occurrences in four time periods is 12 occurrences. c) The Poisson probability function to determine the probability of x occurrences in four time periods is P(x; λ = 3 * 4) = (e^-(3 * 4) * (3 * 4)^x) / x!. d) The probability of three occurrences in one time period is 0.0613 (rounded to four decimal places).
Step-by-step explanation:
a) The appropriate Poisson probability function is given by: P(x; λ) = (e-λ * λx) / x!
b) To find the expected number of occurrences in four time periods, we simply multiply the mean by the number of time periods: 3 * 4 = 12 occurrences.
c) The appropriate Poisson probability function to determine the probability of x occurrences in four time periods is: P(x; λ = 3 * 4) = (e-(3 * 4) * (3 * 4)x) / x!
d) To compute the probability of three occurrences in one time period, we use the Poisson probability function with λ = 3 and x = 3: P(3; 3) = (e-3 * 33) / 3! = 0.0613 (rounded to four decimal places).