| plot.sdi {SDT} | R Documentation |
Plot Method for Objects of Class sdi
Description
S3 method to plot objects of the class sdi.
Usage
## S3 method for class 'sdi'
plot(x, minscore = 1, maxscore = 5, ...)
Arguments
x |
A required object of the class |
minscore, maxscore |
Optional numerics, integer-valued, giving the minimum score (typically 1) or maximum score (typically 4, 5, or 7) used in the scale procedure, respectively. See also ‘Details’. |
... |
Further arguments to be passed are ignored in this function. |
Details
This plot method graphs the results obtained from calculating the
original or adjusted SDI or RAI index. It produces a scatterplot of the
confounded or adjusted external locus component values (y-axis) versus
the confounded or adjusted internal locus component values (x-axis),
respectively. In addition, for comparison, the reference line y = x
(red full line) for visual inspection of the deviation of the two types of
values and the admissible range (gray dashed lines) for the original or
adjusted SDI or RAI index component values are plotted. Points with higher
original or adjusted SDI or RAI overall index values are shown in darker gray
tone.
To define and plot the admissible range, we do need the minscore and
maxscore arguments, where minscore is the minimum score used in
the scale procedure (typically 1), and maxscore is the maximum score
used in the scale procedure (typically 4, 5, or 7). Note that translation
with ‘- minscore’ and averaging are applied in the
definitions of the components of the adjusted SDI or RAI index. The
admissible range in the adjusted measure case is given by [0, maxscore -
minscore], which yields [0, 4] for the default values. The admissible
range in the original index case is the interval [(2 * minscore) +
minscore, (2 * maxscore) + maxscore], that is, [3, 15] for the default
values.
The function gray of the package grDevices is used to
plot the points in the scatterplot at different gray levels determined by
their respective original or adjusted SDI or RAI overall index values.
Value
If the arguments x, minscore, and maxscore are
of required types, plot.sdi produces the plot and invisibly returns
NULL.
Author(s)
Ali Uenlue <ali.uenlue@icloud.com>
References
Uenlue, A. (2016) Adjusting potentially confounded scoring protocols for motivation aggregation in organismic integration theory: An exemplification with the relative autonomy or self-determination index. Frontiers in Educational Psychology, 7(272), 1–4. URL https://doi.org/10.3389/fpsyg.2016.00272.
See Also
The main function of the package, which creates objects of the class
sdi: sdi for the original and adjusted SDI or RAI
index. print.sdi, the S3 method for printing objects of the
class sdi; summary.sdi, the S3 method for summarizing
objects of the class sdi. See also SDT-package for
general information about this package.
Examples
## attach dataset to search path (so a variable can be accessed by name)
attach(learning_motivation)
## adjusted index plot
plot(sdi(intrinsic, identified, introjected, external))
## original index plot
plot(sdi(intrinsic, identified, introjected, external, compute.adjusted = FALSE))