Description Author(s) References

This package performs what is known as the Tukey HSD test in the conventional way. It also uses an algorithm which divides the set of all means in groups and assigns letters to the different groups, allowing for overlapping. This is done for simple experimental designs and schemes. The most usual designs are: Completely Randomized Design (CRD), Randomized Complete Block Design (RCBD) and Latin Squares Design (LSD). The most usual schemes are: Factorial Experiment (FE), Split-Plot Experiment (SPE) and Split-Split-Plot Experiment (SPE).

The package can be used for both balanced or unbalanced (when possible), experiments.

**R** has some functions
(`TukeyHSD`

provided by `stats`

,
`glht`

provided by `multcomp`

,
`HSD.test`

provided by `agricolae`

and
`cld`

provided by `multcomp`

) which also performs
the Tukey test. The `TukeyHSD`

returns intervals based on the range of the
sample means rather than the individual differences. Those intervals are based
on Studentized range statistics and are, in essence, confidence intervals.
This approach has two advantages: the p-value is showed allowing the user to
flexibilize the inferencial decision and also make it possible to plot the
result of the test. However, it has one disadvantage, since the final result is
more difficult to understand and summarize. Others (`glht`

, `cld`

)
are also useful but difficult to manage.
Additionally, most of users of other statistical softwares are very used with
letters grouping the means of the factor tested, making unattractive or
difficult to adapt to the current aproach of **R**.

So, the main aim of this package is make available in **R** environment the
conventional aproach of Tukey test with a set of flexible funtions and
S3 methods.

Jos<e9> Cl<e1>udio Faria (joseclaudio.faria@gmail.com)

Enio Jelihovschi (eniojelihovs@gmail.com)

Ivan Bezerra Allaman (ivanalaman@gmail.com)

Miller, R.G. (1981) *Simultaneous Statistical Inference*. Springer.

Ramalho M.A.P, Ferreira D.F & Oliveira A.C. (2000) *Experimenta<e7><e3>o em Gen<e9>tica
e Melhoramento de Plantas*. Editora UFLA.

Steel, R.G., Torrie, J.H & Dickey D.A. (1997) *Principles and procedures of statistics:
a biometrical approach*. Third Edition.

Yandell, B.S. (1997) *Practical Data Analysis for Designed Experiments*.
Chapman & Hall.

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