goodnessOfFitTest: Chi-square test against specified probabilities In lsr: Companion to "Learning Statistics with R"

Description

Convenience function that runs a chi-square goodness of fit test against specified probabilities. This is a wrapper function intended to be used for pedagogical purposes only.

Usage

 `1` ```goodnessOfFitTest(x, p = NULL) ```

Arguments

 `x` Factor variable containing the raw outcomes. `p` Numeric variable containing the null-hypothesis probabilities (default = all outcomes equally likely)

Details

The `goodnessOfFitTest` function runs the chi-square goodness of fit test of the hypothesis that the outcomes in the factor `x` were generated according to the probabilities in the vector `p`. The probability vector `p` must be a numeric variable of length `nlevels(x)`. If no probabilities are specified, all outcomes are assumed to be equally likely.

Value

An object of class 'gofTest'. When printed, the output is organised into four short sections. The first section lists the name of the test and the variables included. The second lists the null and alternative hypotheses for the test. The third shows the observed frequency table, the expected frequency table under the null hypothesis, and the probabilities specified by the null. The fourth prints out the test results.

`chisq.test`, `associationTest`, `cramersV`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14``` ```# raw data gender <- factor( c( "male","male","male","male","female","female", "female","male","male","male" )) # goodness of fit test against the hypothesis that males and # females occur with equal frequency goodnessOfFitTest( gender ) # goodness of fit test against the hypothesis that males appear # with probability .6 and females with probability .4. goodnessOfFitTest( gender, p=c(.4,.6) ) goodnessOfFitTest( gender, p=c(female=.4,male=.6) ) goodnessOfFitTest( gender, p=c(male=.6,female=.4) ) ```