When he types reports, Tom makes typing errors at an average rate of .7 errors per page. Assume that all the Poisson conditions—independence, etc.—are met. Letting x represent values of the random variable “number of typing errors on a page,” use the Poisson table to
a. Determine the probability that x = 1 (that is, the probability that Tom makes exactly 1 typing error on a randomly selected page).
b. Compute the expected number of typing errors on a page, using the expression E(x) = ∑[x • P(x)].
c. Compare your answer in part b to the value of λ.
d. Compute the variance for the distribution using the general expression σ2 = ∑[(x ─ E(x))2 • P(x)].
e. Compare your answer in part d to the value of λ.