In a study of blood donors 225 were classified as type O and

In a study of blood donors, 225 were classified as type O and 275 had a classification other than type O. what is the probability that a person dose not have type O blood?

Solution

P( person does not have tuype O blood) = 1 - P( person does have type O blood)

P type O blood) = 225 / (225+275) = 0.45

P( person does not ahve type O blood) = 1 - 0.45 = 0.55