Butterworth, missouri, is trying to increase its tourism, a great source of revenue. among other things, butterworth prides itself on its temperate climate. the tourism department would like to include in its glossy new brochure the middle range of temperatures that occur on 90% of the days there. a check with the national weather service finds that the average temperature in butterworth is 76 degrees with a standard deviation of 5.7 (the temperatures were normally distributed). the tourism department by finding the two temperatures that cut off the middle 90% of temperatures in butterworth.