ConfidenceLevel

As of Version 7.0, ConfidenceLevel is part of the built-in Mathematica kernel.

ConfidenceLevel
is an option to statistical functions that specifies the confidence level for confidence intervals.

To use ConfidenceLevel, you first need to load the Hypothesis Testing Package using Needs["HypothesisTesting`"].

For confidence level , the probability that a confidence interval will contain the true value is .

The value of ConfidenceLevel can be any number between 0 and 1. The default setting is 0.95.

Needs["HypothesisTesting`"]

A 99% confidence interval from a normal distribution: