Question: Among persons donating blood to a clinic, 0.5% have a very rare RH blood type.

a. 800 people donate blood at the clinic during one year. Use the table of Poisson CDF (Table 3 on page 767) to find the probability that at least five people have this RH blood type. (7)

b. (3 extra credit, no partial credit) The clinic needs at least four donors of this RH blood type per year. Use the Poisson table to find how many people must donate blood to have the probability of at least five donors of this blood type equal or greater than 0.9?