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Unformatted text preview: STAT 100A HWIII
Problem 1: Suppose 1% of the population is inﬂicted with a particular disease. For a medical test, if a person has the disease, then 95% chance the person will be tested positive. If a person does not have the disease, then 90% chance the person will be tested negative. Using precise notation, calculate (1) The probability that a randomly selected person will be tested positive. (2) If the person is tested positive, what is the chance that he or she has the disease? If the person is tested negative, what is the chance that the person does not have this disease? Problem 2: Suppose we ﬂip a coin 5 times independently. Suppose the probability of getting a head in each ﬂip is .4. Let X be the number of heads. Calculate P (X = k ), where k = 0, 1, ..., 5. Problem 3: Suppose there are 6 red balls and 5 blue balls in an urn. Suppose we randomly pick 4 balls. Let X be the number of red balls we pick. Calculate P (X = k ), where k = 0, 1, ..., 4. 1 ...
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- Fall '10