1. There are four ABO blood types: A, B, AB and O. Your blood type is also determined by RH status: Rh+ or Rh-. That leaves us with eight possible blood types: A+, A-, B+, B-, AB+, AB-, O+, O-. Among a group of 50 patients, 18 of them have type A+, 3 have type A-, 4 have B+, 2 have B-, 4 have AB+, 2 has AB-, 13 have type O+, and 4 have type O-. A random sample of 8 patients will be selected from this group.
2. How many different samples are possible? (2 marks)

1. How many different samples of size 8 are possible subject to the constraint that no 2 patients may have the same blood type? (2 marks)
2. What is the probability that a random sample of 8 patients from this group has no two patients with the same blood type? (2 marks)