distractor_plot: Distractor plot

In dexter: Data Management and Analysis of Tests

Distractor plot

Description

Produce a diagnostic distractor plot for an item

Usage

distractor_plot(
  dataSrc,
  item_id,
  predicate = NULL,
  legend = TRUE,
  curtains = 10,
  adjust = 1,
  col = NULL,
  ...
)

Arguments

dataSrc	a connection to a dexter database or a data.frame with columns: person_id, item_id, response, item_score and optionally booklet_id
item_id	The ID of the item to plot. A separate plot will be produced for each booklet that contains the item, or an error message if the item_id is not known. Each plot contains a non-parametric regression of each possible response on the total score.
predicate	An optional expression to subset data, if NULL all data is used
legend	logical, whether to include the legend. default is TRUE
curtains	100*the tail probability of the sum scores to be shaded. Default is 10. Set to 0 to have no curtains shown at all.
adjust	factor to adjust the smoothing bandwidth respective to the default value
col	vector of colors to use for plotting. The names of the vector can be responses. If the vector is not named, colors are assigned to the most frequent responses first.
...	further arguments to plot.

Details

Customization of title and subtitle can be done by using the arguments main and sub. These arguments can contain references to the variables item_id, booklet_id, item_position(if available), pvalue, rit and rir. References are made by prefixing these variables with a dollar sign. Variable names may be postfixed with a sprintf style format string, e.g. distractor_plot(db, main='item: $item_id', sub='Item rest correlation: $rir:.2f')

Value

Silently, a data.frame of response categories and colors used. Potentially useful if you want to customize the legend or print it separately

dexter documentation built on Sept. 11, 2024, 6:42 p.m.