(5) 2. A test for the presence of a certain disease has probability .02 of giving a false-positive . reading (a positive test for a healthy person) and probability .03 of giving a false-negative result. Suppose that four individuals are tested, two of vvhom have the disease and two of Whom do not. Let X = the number of positive readings. ' a) Does X have a binomial distribution ? Explain your reasoning. b) What is the probability that at most two of the four test results are positive ? c) Find the expected number of positive tests