11-30. Two spray-bottle rug cleaners were tested for their ability to remove a specific type of stain. The first was deemed successful in x = 37 out of nX = 70 independent trials and the second was judged successful in y = 62 out of nY = 85 independent trials. If pX (respectively, pY) is the true proportion of times the first (respectively, the second) cleaner is successful at removing the specific stain, determine an approximate 95% confidence interval for pX − pY.