(84) :normalcdf(lower, upper)
For a normal curve, this computes the area between z-values lower and upper.
(84) :normalcdf(lower, upper, mean, stDev)
For a normal curve with mean mean and standard deviation stDev, this computes the area between values lower and upper.
- 2ND + VARS (DISTR)
computes the area onder the whole of a normal curve, at least to the calculator's precision. Returns 1.