Price scanners are widely used in U. S supermarkets. While they are fast and easy to use, they also make mistakes. A recent Federal Trade Commission selected a random sample of 800 and 900 merchandise from supermarket scanners and department store scanners, and found that 28 and 82 errored respectively. Obtain a 95% confidence interval for the difference between the error rates of the two scanners and interpret your result in terms of the problem.