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- Suppose the frequency of the A, B, and O alleles are
0.5, 0.2, and 0.3.
- What is the probability of an AB individual?
**2*0.5*0.2 = 0.20** - What is the probability of an O individual?
**0.3*0.3 = 0.09** - What is the probability of an A individual?
**AA or Ai = 0.5*0.5 + 2*0.5*0.3 = 0.55**

- What is the probability of an AB individual?
- If the frequency of the Rh negative allele is 0.2, using the same A, B, and O frequencies as above
- What is the probability of an Rh negative individual?
**0.2*0.2 = 0.04** - What is the probability of an Rh heterozygote?
**2*0.2*0.8 = 0.32** - What is the probability of an O negative individual?
**From your answers above, = 0.09*0.04 = 0.0036** - What is the probability of an A positive individual?
**Pro(Positive) = Prob(++ or +-) = 0.8*0.8 + 0.32 = 0.96**We can also obtain this by using Prob(Positive) = 1-Prob(negative) = 1-0.04 = 0.96

**Hence Prob(A and positive) = 0.55*0.96 = 0.528**

- What is the probability of an Rh negative individual?
- Suppose the frequency of a particular blood type is 0.01 (one in a hundred).
- What is the probability that we do not see this blood type if we sample 50 individual?
**Prob(none in 50) = 0.99**^{50}= 0.605 - What is the probability of not seeing this blood type in a sample of 100 individuals?
**Prob(none in 100) = 0.99**^{100}= 0.366 - How many individuals do we need to sample to have a 90 percent probability of seeing AT LEAST one individual with this blood type?
**Prob(at least one in x = 0.9) means Prob(none in x) = 0.10 or .99**^{x}= 0.10log(.99

^{x}) = log(0.10) or x* log(.99 ) = log(0.10) or**x = log(0.10) / log(.99 ) = 229**

- What is the probability that we do not see this blood type if we sample 50 individual?