HOW TO FIND THE AREA UNDER THE NORMAL CURVE ON THE TI83

Steps	Key Sequence	Screens
1. Find the normal curve function	Press 2nd then VARS
	Press 2 (for normalcdf)
** This function has four (4) arguments. They are: lower bound, upper bound, mean, standard deviation. **
Example 1: Let mean = 64.5 and standard deviation = 2.5
** To type in E use 2nd then comma. To type in a negative sign, use (-) button.
Case 1: Find the area to the left of x = 68 on the normal curve.	normalcdf(-1E99,68, 64.5,2.5)
	ENTER
Case 2: Find the area to the right of x = 65 on the normal curve.	normalcdf(65,1E99, 64.5,2.5)
	ENTER
Case 3: Find the area between x = 63 and x = 66 on the normal curve.	normalcdf(63,66, 64.5,2.5)
	ENTER
Example 2: Standard Normal Curve where mean = 0 and standard deviation = 1
** The standard normal curve uses z, where z = (x – mean)/(standard deviation).
** The normalcdf function will use ONLY two (2) arguments. They are: lower bound and upper bound. By default mean = 0 and standard deviation = 1.
Case 1: Find the area to the left of z = 1.5 on the normal curve.	normalcdf(-1E99,1.5)
	ENTER
Case 2: Find the area to the right of z = 1.3 on the normal curve.	normalcdf(1.3,1E99)
	ENTER
Case 3: Find the area between z = 0.7 and z = 0.9 on the normal curve.	normalcdf(0.7,0.9)
	ENTER