Two operators perform the same operation of applying a plastic coating to Plexiglas. We want to estimate the difference in the proportion of nonconforming parts produced by the two operators. A random sample of 100 parts from the first operator shows that 6 are nonconforming. A random sample of 200parts from the second operator shows that 10 are nonconforming. Find a 90% confidence interval for the difference in the proportion of nonconforming parts produced by the two operators. what is the conclusion?