The results are fairly accurate, with worst-case errors of 0.02%.

**For the mathematically inclined**, the algorithm simply evaluates
an eighth-degree polynomial approximation of the cumulative density function
at the two endpoints and subtracts. The polynomial approximation
is based on mutually orthogonal polynomials on [-4.5,4.5]. The truth is,
using the built in integrator on the formula for the normal curve is sometimes
faster and always more accurate; this was an interesting experiment, though.

Just enter this program in your TI-85 and run.

You can download a binary version for linking
to your calculator...

...or type in the program below.

If you type, please proofread your typing carefully; being off by just
one character will likely cause serious errors.
**Note that uppercase and lowercase are NOT interchangeable**.

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