

   SSttuuddeenntt''ss SSlleeeepp DDaattaa

        data(sleep)

   FFoorrmmaatt::

        A data frame with 20 observations on 2 variables.

         [, 1]     extra     numeric     increase in hours of sleep
         [, 2]     group     factor      patient group

   DDeessccrriippttiioonn::

        Data which show the effect of two soporific drugs
        (increase in hours of sleep) on groups consisting of 10
        patients each.

   SSoouurrccee::

        Student (1908), The probable error of the mean.
        Biometrika, 6, 20.

   RReeffeerreenncceess::

        Scheff'e, Henry (1959): The analysis of variance.  New
        York, NY: Wiley.

   EExxaammpplleess::

        data(sleep)
        ## ANOVA
        anova(lm(extra ~ group, data = sleep))

