a variable is normally distributed with mean 20 and standard deviation 9. use your graphing calculator to find each of the following areas. write your answers in decimal form. round to the nearest thousandth as needed. a) find the area to the left of 20. 0.599 incorrect b) find the area to the left of 16. 0.227 incorrect c) find the area to the right of 18. 0.5 incorrect d) find the area to the right of 25. e) find the area between 16 and 30.