1. Assume you know that number of complaints coming in a phone center averages 4.2 every ten minutes. Suppose that the number of calls follows Poisson distribution. Find out the probability that there are exactly three calls throughout the next ten minutes?
2. An auditor reviewing invoices of small company finds that there're errors in 1.5% of them. If the auditor looks at 500 invoices, find out the probability that he finds more than three invoices with errors?