variance.test: One Sample Variance Test of a Normal Population
In LearningStats: Elemental Descriptive and Inferential Statistics

Description Usage Arguments Details Value Examples

variance.test allows to compute hypothesis tests for the variance of a Normal population in both scenarios: known or unknown population mean.

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variance.test(x = NULL, s = NULL, sc = NULL, smu = NULL, mu = NULL,
  n = NULL, sigma02, alternative = "two.sided", alpha = 0.05,
  plot = TRUE, lwd = 1)

`x`	a numeric vector containing the sample.
`s`	a single numeric value corresponding with the sample standard deviation.
`sc`	a single numeric value corresponding with the cuasi-standard deviation.
`smu`	if known, a single numeric value corresponding with the estimation of the standard deviation for known population mean.
`mu`	if known, a single numeric value corresponding with the population mean. Even when the user provides smu, mu is still needed.
`n`	a single positive integer corresponding with the sample size; not needed if the sample is provided.
`sigma02`	a single number corresponding with the variance to test.
`alternative`	a character string specifying the alternative hypothesis, must be one of "`two.sided`" (default), "`greater`" or "`less`".
`alpha`	a single number in (0,1), significance level.
`plot`	a logical value indicating whether to display a graph including the test statistic value for the sample, its distribution, the rejection region and p-value.
`lwd`	a single number indicating the line width of the plot.

The formula interface is applicable when the user provides the sample or values of the sample characteristics (cuasi-standard deviation or sample standard deviation).

A list with class "lstest" and "htest" containing the following components:

`statistic`	the value of the test statistic.
`parameter`	the degrees of freedom of the statistic's distribution.
`p.value`	the p-value of the test.
`estimate`	the cuasi-variance.
`null.value`	the value specified by the null.
`alternative`	a character string describing the alternative.
`method`	a character string indicating the method used.
`data.name`	a character string giving the names of the data.
`alpha`	the significance level.
`dist.name`	a character string indicating the distribution of the test statistic.
`statformula`	a character string with the statistic's formula.
`reject.region`	a character string with the reject region.
`unit`	a character string with the units.

x <- rnorm(50, mean = 1, sd = 2)
# unknown population mean
variance.test(x, sigma02 = 3.5)
variance.test(sc = sd(x), n = 50, sigma02 = 3.5)
# known population mean
variance.test(x, sigma02 = 3.5, mu = 1)
smu <- Smu(x, mu = 1)
variance.test(smu = smu, n = 50, sigma02 = 3.5)