# sigma2.test: Test of a variance In TRSbook: Functions and Datasets to Accompany the Book "The R Software: Fundamentals of Programming and Statistical Analysis"

## Description

Comparing the theoretical variance with a reference value

## Usage

 `1` ```sigma2.test(x, alternative = "two.sided", var0 = 1, conf.level = 0.95) ```

## Arguments

 `x` numeric vector `alternative` Alternative hypothesis for the test. Either two sided ("two.sided"), one sided to the left ("less") or one sided to the right ("greater"). Default is "two.sided". `var0` value of reference for the variance `conf.level` confidence level

## Value

Returns a list:

 `statistic` Value of the test statistic `parameter` degrees of freedom `p.value` p-value of the test `conf.int` confidence interval `estimate` sample variance `null.value` value of reference for the variance `alternative` Alternative hypothesis for the test `method` "One-sample Chi-squared test for given variance" `data.name` name of the data set

## Author(s)

Lafaye de Micheaux Pierre <lafaye@unsw.edu.au>, Remy Drouilhet <Remy.Drouilhet@upmf-grenoble.fr>, Liquet Benoit <b.liquet@uq.edu.au>

## References

Chapter 13 (Confidence Intervals and Hypothesis Testing) from the book: The R Software, Fundamentals of Programming and Statistical Analysis

## Examples

 ```1 2``` ```data(NUTRIELDERLY) sigma2.test(NUTRIELDERLY\$weight,conf.level=0.9)\$conf ```

### Example output

```Loading required package: xtable
gdata: read.xls support for 'XLS' (Excel 97-2004) files ENABLED.

gdata: read.xls support for 'XLSX' (Excel 2007+) files ENABLED.

Attaching package: 'gdata'

The following object is masked from 'package:stats':

nobs

The following object is masked from 'package:utils':

object.size

The following object is masked from 'package:base':

startsWith