A coffee manufacturer is interested in whether the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers. Assume the population standard deviation for those drinking regular coffee is 1.23 cups per day and 1.37 cups per day for those drinking decaffeinated coffee. A random sample of 46 regular-coffee drinkers showed a mean of 4.36 cups per day. A sample of 36 decaffeinated-coffee drinkers showed a mean of 5.64 cups per day.