# TI-BASIC:Normalpdf

**Command Summary**

Evaluates the normal probability density function at a point.

**Command Syntax**

normalpdf(*x*[,*μ*, *σ*])

**Menu Location**

Press:

- 2ND DISTR to access the distribution menu
- ENTER to select normalpdf(.

TI-83/84/+/SE

2 bytes

normalpdf( is the normal (Gaussian) probability density function.

Since the normal distribution is continuous, the value of normalpdf( doesn't represent an actual probability - in fact, one of the only uses for this command is to draw a graph of the normal curve. You could also use it for various calculus purposes, such as finding inflection points.

The command can be used in two ways: normalpdf(*x*) will evaluate the standard normal p.d.f. (with mean at 0 and a standard deviation of 1) at *x*, and normalpdf(*x*,*μ*,*σ*) will work for an arbitrary normal curve, with mean *μ* and standard deviation *σ*.

# Formulas

For the standard normal distribution, normalpdf(*x*) is defined as
Template:TI-BASIC:Math \, e^{-\frac1{2}x^2}
}}

For other normal distributions, normalpdf( is defined in terms of the standard distribution: Template:TI-BASIC:Math