According to a local study, 80 per cent of workers in US work in an envitonment that could endanger their visual. If 20 US workers selected randomly as a sample, what is the probability

a) that exactly 16 workers work in such environment?

b) that more than 17 workers work in such environment?

c) that exactly 4 workers not work in such environment?

d) fewer than 3 workers the number not work in such environment?

General probability distribution: Mean or expected value u = E(X) = EX . P(X) Variance 0 = E ( X-/). P(X) Standard deviation o = Vo2 Binomial Distribution: Mean u = n. p Variance 62 = n .p. q Standard deviation = n. p. q X n-X Probability P(X) = "cr.p q for OSX Sn Poisson Distribution: var(x) = ProbabilityP (x) = - x ! for x = 0, 1, 2, 3 ... ... Normal Distribution Probability z =