discrete random variable questions

QUESTION 5 a) Give TWO (2) characteristics of discrete random variable. {2 marks) b) A book seller sells a special educational book package that consists of five books per package. A customer can purchase the whole set of five books or each book individually. The probability distribution of Y. the number at books purchase from each package, is given as follow. i) Given that E0!) = 2.75. find the values of m. (3 marks) ii) Find the probability that a customer purchase at most four books. (2 marks) iii) Calculate E (Y2 2v + 2). (4 marks)