a variable is normally distributed with mean 21 and standard deviation 7. 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 24. b) find the area to the left of 17. c) find the area to the right of 19. d) find the area to the right of 25. e) find the area between 17 and 30.