1. Sam will read either one chapter of his probability book or one chapter of his history book. If the number of misprints in a chapter of his prob- ability book is Poisson distributed with mean 2 and if the number of misprints in his history chapter is Poisson distributed with mean 5, then assuming Sam is equally likely to choose either book, what is the expected number of misprints that Sam will come across?
2. A coin, having probability p of coming up heads, is to be successively ?ipped until the ?rst head appears. What is the expected number of ?ips required?