chisquaredist

This function is the cumulative chi-square distribution function. It returns the probability that a chi-square distributed random variable is less than a specified independent variable value.

A chi-square random variable is defined as a sum of squares of independent standard normal distribution variables. The number of normal variables in the sum is called the degrees of freedom.

This distribution is used in goodness-of-fit measures. It describes the distribution of sample variance for a set of normally distributed observations and describes the distribution of the residual sum of squares in regression.

Syntax

chisquaredist(x,n)

Example

Suppose a random variable X is chi-square distributed with 11 degrees of freedom. To compute the probability that the values of this variable are less than 5, we calculate:

chisquaredist(5,11) = .06883

関連情報

• chisquareinv
• chisquareden