Unleaded gasoline must meet certain federal standards. The octane number for a particular brand must be at least 89. The standard deviation of the octane number is estimated to be 4. It is preferred to accept shipments for which the average octane number is 94 about 95% of the time.
Also, for those shipments that have an average octane number of 86, the probability of acceptance is desired to be 0.15. Find the parameters of a variable sampling plan.