We can obtain the normal curve area between two sample points (on the X-axis) by
using the Cumulative Distribution Function (CDF). The CDF at any point on the x-
axis is the total area under the curve to the left of that point. We can obtain the
percentage of area in normal curve for each regionby subtracting the CDF at the x-
Value of region's lower boundary from the CDF at the x-Value of the region's upper
boundary.