The book Code Complete by Steve McDonnell estimates that there are 15 to 50 errors per 1,000 lines of delivered code for computer programs. Assume that for a particular software package, the error rate is 21 per 1,000 lines of code and that the number of errors per 1,000 lines of code follows a Poisson distribution.
(a)
What is the probability that a portion of code for this computer package that contains 250 lines of code contains no errors? (Round your answer to four decimal places.)