A random sample of 500 workers engaged in research and devel

A random sample of 500 workers engaged in research and development during 1982 is selected. Of these, 178 earn over $72,000 per year. Of the 450 workers in R&D studies during 1983, 220 earn in excess of $72,000 per year. Find the 95% confidence interval for the difference between the 1982’s and 1983’s proportion of workers who earn over $36,000. What common size must we take from the populations of R&D workers in each of the years 1982 and 1983 to estimate p1 p2 to within 0.02 with 90% confidence

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