SNK.test {agricolae} | R Documentation

## Student-Newman-Keuls (SNK)

### Description

SNK is derived from Tukey, but it is less conservative (finds more differences). Tukey controls the error for all comparisons, where SNK only controls for comparisons under consideration. The level by alpha default is 0.05.

### Usage

    SNK.test(y, trt, DFerror, MSerror, alpha = 0.05, group=TRUE, main = NULL,console=FALSE)

### Arguments

`y` | model(aov or lm) or answer of the experimental unit
`trt` | Constant( only y=model) or vector treatment applied to each experimental unit
`DFerror` | Degree free
`MSerror` | Mean Square Error
`alpha` | Significant level
`group` | TRUE or FALSE
`main` | Title
`console` | logical, print output

### Details

It is necessary first makes a analysis of variance.

### Value

`statistics` | Statistics of the model
`parameters` | Design parameters
`snk` | Critical Range Table
`means` | Statistical summary of the study variable
`comparison` | Comparison between treatments
`groups` | Formation of treatment groups

### Author(s)

Felipe de Mendiburu

### References

1. Principles and procedures of statistics a biometrical approach Steel & Torry & Dickey. Third Edition 1997
2. Multiple comparisons theory and methods. Departament of statistics the Ohio State University. USA, 1996. Jason C. Hsu. Chapman Hall/CRC.

### See Also

`BIB.test`, `DAU.test`, `duncan.test`, `durbin.test`, `friedman`, `HSD.test`, `kruskal`, `LSD.test`, `Median.test`, `PBIB.test`, `REGW.test`, `scheffe.test`, `waerden.test`, `waller.test`, `plot.group`

### Examples

    library(agricolae)
    data(sweetpotato)
    model<-aov(yield~virus,data=sweetpotato)
    out <- SNK.test(model,"virus", console=TRUE,
    main="Yield of sweetpotato. Dealt with different virus")
    print(SNK.test(model,"virus", group=FALSE))
    # version old SNK.test()
    df<-df.residual(model)
    MSerror<-deviance(model)/df
    out <- with(sweetpotato,SNK.test(yield,virus,df,MSerror, group=TRUE))
    print(out$groups)

[Package agricolae version 1.2-9 Index]