The normal distribution describes many natural phenomena, from measurement errors to heights of people. Its bell-shaped curve is defined by the density function
The cumulative distribution function (CDF) gives the probability that a random variable is less than . It is expressed in terms of the error function , which integrates the bell curve.
Statistics, physics, finance, and many other fields rely on the normal distribution. When dealing with standard scores, confidence intervals, or noise models, you often need quick access to its PDF and CDF values. This tool computes them for any mean and standard deviation .
If , , and , the PDF evaluates to and the CDF to . You can verify these values in standard statistical tables.
The script below uses math.js
for accurate evaluation of the error function. By substituting your values into the formulas, it returns the density and cumulative probability rounded to six decimals.
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