boxplot                 package:base                 R Documentation

_B_o_x _P_l_o_t_s

_D_e_s_c_r_i_p_t_i_o_n:

     Produce box-and-whisker plot(s) of the given (grouped) values.

_U_s_a_g_e:

     boxplot(x, ...)
     boxplot.default(x, ..., range = 1.5, width = NULL,
             varwidth = FALSE, notch = FALSE, names, boxwex = 0.8,
             data = parent.frame(), plot = TRUE,
             border = par("fg"), col = NULL, log = "", pars = NULL,
             horizontal = FALSE, add = FALSE)
     boxplot.formula(formula, data = NULL, subset, na.action, ...)

_A_r_g_u_m_e_n_t_s:

       x: an R object.

     ...: methods may have additional arguments.

  x, ...: the data from which the boxplots are to be produced. The data
          can be specified as separate vectors, each corresponding to a
          component boxplot, or as a single list containing such
          vectors.  Alternatively a symbolic specification of the form
          `x ~ g' can be given, indicating that the observations in the
          vector `x' are to be grouped according to the levels of the
          `factor' `g'.  In this case the argument `data' can be used
          to provide values for the variables in the specification.
          `NA's are allowed in the data.

   range: this determines how far the plot whiskers extend out from the
          box.  If `range' is positive, the whiskers extend to the most
          extreme data point which is no more than `range' times the
          interquartile range from the box. A value of zero causes the
          whiskers to extend to the data extremes.

   width: a vector giving the relative widths of the boxes making up
          the plot.

varwidth: if `varwidth' is `TRUE', the boxes are drawn with widths
          proportional to the square-roots of the number of
          observations in the groups.

   notch: if `notch' is `TRUE', a notch is drawn in each side of the
          boxes.  If the notches of two plots do not overlap then the
          medians are significantly different at the 5 percent level.

   names: group labels which will be printed under each boxplot.

  boxwex: a scale factor to be applied to all boxes.  When there are
          only a few groups, the appearance of the plot can be improved
          by making the boxes narrower.

    data: `data.frame', `list', or `environment' in which variable
          names are evaluated when `x' is a formula.

    plot: if `TRUE' (the default) then a boxplot is produced.  If not,
          the summaries which the boxplots are based on are returned.

  border: an optional vector of colors for the outlines of the
          boxplots.  The values in `border' are recycled if the length
          of `border' is less than the number of plots.

     col: if `col' is non-null it is assumed to contain colors to be
          used to col the bodies of the box plots.

     log: character indicating if x or y or both coordinates should be
          plotted in log scale.

    pars: graphical parameters can also be passed as arguments to
          `boxplot'.

horizontal: logical indicating if the  boxplots should be horizontal;
          default `FALSE' means vertical boxes.

     add: logical, if true add boxplot to current plot.

 formula: a formula, such as `y ~ x'.

    data: a data.frame (or list) from which the variables in `formula'
          should be taken.

  subset: an optional vector specifying a subset of observations to be
          used in the fitting process.

na.action: a function which indicates what should happen when the data
          contain `NA's.

     ...: further arguments to the default boxplot method and graphical
          parameters may also be passed as arguments, see `par'.

_D_e_t_a_i_l_s:

     This is a generic function.  It currently has a default method
     (`boxplot.default') and a formula interface (`boxplot.formula').

_V_a_l_u_e:

     List with the following components: 

   stats: a matrix, each column contains the extreme of the lower
          whisker, the lower hinge, the median, the upper hinge and the
          extreme of the upper whisker for one group/plot.

       n: a vector with the number of observations in each group.

    conf: a matrix where each column contains the lower and upper
          extremes of the notch.

     out: the values of any data points which lie beyond the extremes
          of the whiskers.

   group: a vector of the same length as `out' whose elements indicate
          which group the outlier belongs to

   names: a vector of names for the groups

_S_e_e _A_l_s_o:

     `boxplot.stats' which does the computation, `bxp' for the
     plotting, and `stripplot' for an alternative (with small data
     sets).

_E_x_a_m_p_l_e_s:

     ## boxplot on a formula:
     data(InsectSprays)
     boxplot(count ~ spray, data = InsectSprays, col = "lightgray")
     # *add* notches (somewhat funny here):
     boxplot(count ~ spray, data = InsectSprays,
             notch = TRUE, add = TRUE, col = "blue")

     data(OrchardSprays)
     boxplot(decrease ~ treatment, data = OrchardSprays,
             log = "y", col="bisque")

     ## boxplot on a matrix:
     mat <- cbind(Uni05 = (1:100)/21, Norm = rnorm(100),
                  T5 = rt(100, df = 5), Gam2 = rgamma(100, shape = 2))
     boxplot(data.frame(mat), main = "boxplot(data.frame(mat), main = ...)")
     par(las=1)# all axis labels horizontal
     boxplot(data.frame(mat), main = "boxplot(*, horizontal = TRUE)",
             horizontal = TRUE)

