Plot Pearson's Chi2-Test of multiple contingency tables

Plot p-values of Pearson's Chi2-tests for multiple contingency tables as ellipses or tiles. Requires a data frame with dichotomous (dummy) variables. Calculation of Chi2-matrix taken from Tales of R.

sjp.chi2(df, title = "Pearson's Chi2-Test of Independence",
  axis.labels = NULL, wrap.title = 50, wrap.labels = 20,
  show.legend = FALSE, legend.title = NULL, prnt.plot = TRUE)

Arguments

df	A data frame with (dichotomous) factor variables.
title	character vector, used as plot title. Depending on plot type and function, will be set automatically. If title = "", no title is printed. For effect-plots, may also be a character vector of length > 1, to define titles for each sub-plot or facet.
axis.labels	character vector with labels used as axis labels. Optional argument, since in most cases, axis labels are set automatically.
wrap.title	numeric, determines how many chars of the plot title are displayed in one line and when a line break is inserted.
wrap.labels	numeric, determines how many chars of the value, variable or axis labels are displayed in one line and when a line break is inserted.
show.legend	logical, if TRUE, and depending on plot type and function, a legend is added to the plot.
legend.title	character vector, used as title for the plot legend.
prnt.plot	logical, if TRUE (default), plots the results as graph. Use FALSE if you don't want to plot any graphs. In either case, the ggplot-object will be returned as value.

Value

(Insisibily) returns the ggplot-object with the complete plot (plot) as well as the data frame that was used for setting up the ggplot-object (mydf).

See also

Tales of R.

Examples

# create data frame with 5 dichotomous (dummy) variables
mydf <- data.frame(as.factor(sample(1:2, 100, replace=TRUE)),
                   as.factor(sample(1:2, 100, replace=TRUE)),
                   as.factor(sample(1:2, 100, replace=TRUE)),
                   as.factor(sample(1:2, 100, replace=TRUE)),
                   as.factor(sample(1:2, 100, replace=TRUE)))
# create variable labels
items <- list(c("Item 1", "Item 2", "Item 3", "Item 4", "Item 5"))

# plot Chi2-contingency-table
sjp.chi2(mydf, axis.labels = items)