Gives specific statistical methods for addressing the following questions: a) Given a population of items from which a Sample of y2 items has been drawn, x of the Sample items are found to show a specified characteristic. What Proportion of the population has that characteristic?, b) Is the Proportion estimated in a) different from a nominal (specified) value?, c) Given two distinct populations, are the proportions with the characteristic in the two populations different? and d) In b) and c) how many items must be sampled in the population(s) to be sufficiently Sure that the result of the test is correct?