Question

Suppose that the probability that an item produced by a certain machine will be defective is 0.2. A sample of 12 items is chosen. Let X be the number of defectives among the selected 12 items.
(a) Find the probability of at most 1 defective item.
(b) Find the probability of at least 1 defective item
(c) Find the probability of 3 or 4 defective items
(d) Find the expected value and standard deviation.