Reference no: EM132851779

In a certain institute, it is known that 15% of all student score grade "A" in Statistics 101. Four male students and five female students are selected at random from the Statistics 101 class. With appropriate assumption(s), compute the probability that in the selected group

(a) 3 students in the selected group score "A";

(b) 1 male and 2 female students score "A";

(c) at most 2 female students and at least 1 male student score "A".

The telephone exchange inside an office building has a number of outside lines of which, on average, 3 are being used at any instant. Assuming that the number if lines in use at any instant follows a Poisson distribution. Applying the Poisson model, evaluate the minimum number of outside lines required if there is a probability of more than 0.9 that, at any given instant, at least one of the lines is not being used.