A machine producing microchips is known to produce 20% defective items. In
order to maintain a system of quality control, the manager selects a sample of 10
every hour and examine them. From a sample of 10, calculate the
(i) probability that none of them are defective. (2 marks)
(ii) probability that at most 2 are defective. (3 marks)
(iii) mean and standard deviation for the number of left-handed students.
(2 marks)
(iv) If 50 batches of samples were taken, what is the probability that 10 batches
are non-defective? (3 marks)