This function is used by the Summary Statistics dialog. It calculates
summary statistics for selected columns of a data frame. Summary may be
calculated withing groups based on one or more grouping variables.
the data frame in which to find the variables named in
variables.
OPTIONAL ARGUMENTS:
variables
variables for which summaries are to be calculated.
grouping.variables
One or more variables to use for grouping. Observations will be binned
based on the grouping variables, and summaries will be calculated within
each group.
max.numeric.levels
the maximum number of unique values to consider as separate categories.
Numeric variables with more than this many unique values
will be binned.
nbins
the number of bins to use for numeric variables.
The bins are of equal width and cover the range of the variable.
min.p
logical flag indicating whether to calculate the minimum value.
first.quant.p
logical flag indicating whether to calculate the first quantile.
mean.p
logical flag indicating whether to calculate the mean.
median.p
logical flag indicating whether to calculate the median.
third.quant.p
logical flag indicating whether to calculate the third quantile.
max.p
logical flag indicating whether to calculate the maximum.
nobs.p
logical flag indicating whether to calculate the number of observations.
valid.n.p
logical flag indicating whether to calculate the number of non-missing
observations.
var.p
logical flag indicating whether to calculate the variance.
stdev.p
logical flag indicating whether to calculate the standard deviation.
sum.p
logical flag indicating whether to calculate the sum.
factors.too.p
logical flag indicating whether to include summaries for factors. If so,
counts of factors will be included in the results.
print.p
logical flag indicating whether to print the results.
subset
subsetting expression for rows.
VALUE:
If there are any columns of class
factor in the data frame, then this
object is a list with two components, each of class
table. If no columns
are of class
factor, or if factor summaries were not requested, then this
object is a list with one component.
If grouping variables are specified, the result will be a list of class
by,
with one component for each combination of grouping variables. The structure
of each component is determine by whether factors are present, as indicated
in the previous paragraph.
DETAILS:
Note that although this function is related to the
summary function, it does
not actually call this function. This function provides a more extensive
set of results than does
summary.
The number of significant digits displayed is determined by the
digits
option. See
options for details on changing this value. See
print.table
for more information on control of
table formatting.