The manufacturers of Good-O use two different types of machinesto fill their 25 kg packs of dried dog food. On the basis of randomsamples of size 15 and 18 from output from machines 1 and 2respectively, the mean and standard deviation of the weight of thepacks of dog food produced were found to be 28.99 kg and 0.142 kgfor machine 1 and 26.376 kg and 0.383 kg for machine 2. Hence,under the usual assumptions, determine a 95% confidence intervalfor the difference between the average weight of the output ofmachine 1 and machine 2. Use machine 1 minus machine 2, stating theupper limit of the interval correct to three decimal places.
