A machine produces 1000 rubber 0=rings per hour. Each ring has a .9 probability of meeting a thickness specification.
a) Using a direct binomal calculation find the probability that during a given hour fewer than 890 0-rings meet the thickness specification.
b) Using a normal approximation estimate the probability that a during given hour fewer than 890 0-rings meet the specification.
c) What is the expected number of 0-rings that meet the specification per hour?
d) Using your answer to either A or B and assuming independence between hours find the probability that the machine meets specifications on at least 890 0-rings for each of 4 consecutive hours.
e) Using your answer to with A or B and assuming independence between hours find the probability the machine meets specifications on at least 890 0-rings on exactly 2 out of 4 consecutive hours.