Problem 3. Hypothesis test with a continuous observation
Let Θ be a Bernoulli random variable that indicates which one of two hypotheses is true, and let P(Θ = 1) = p. Under the hypothesis Θ = 0, the random variable X has a normal distribution with mean 0 and variance 1. Under the alternative hypothesis Θ = 1, X has a normal distribution with mean 2 and variance 1.
Consider the MAP rule for deciding between the two hypotheses, given that X = x.
1. Suppose for this part of the problem that p = 2/3. The MAP rule can choose in favor of the hypothesis Θ = 1 if and only if x ≥ c1. Find the value of c1.
2. For this part, assume again that p = 2/3. Find the conditional probability of error for the MAP decision rule, given that the hypothesis Θ = 0 is true.
P(error|Θ = 0)
3. Find the overall (unconditional) probability of error associated with the MAP rule for p = 1/2.
You may want to consult to standard normal table.