2. Assume the readings on thermometers are normally distributed with a mean of 0C and a standard deviation of 1.00C. A thermometer is randomly selected and tested. a. Draw a sketch and find the temperature reading corresponding to P81, the 81st percentile. This is the temperature reading separating the bottom 81% from the top 19%. b. The temperature for P81 is approximately _____degrees. Solution For the 81st percentile z = 0.85 = (x - M)/SD Hence, x = 0.85 C.