tif: Test information function
In irtoys: A Collection of Functions Related to Item Response Theory (IRT)
tif R Documentation
Test information function
Description
Returns the test information function (TIF) of the 3PL (1PL, 2PL) model. The
TIF is the sum of the item information functions (IIF) in a test, and
indicates the precision of measurement that can be achieved with the test at
any value of the latent variable, bein inversely related to measurement
variance.
Usage
tif(ip, x = NULL)
Arguments
ip
Item parameters: the output of est.
x
The values of the latent variable (θ in the equation
above), at which the TIF will be evaluated. If not given, 99 values spaced
evenly between -4 and +4 will be used, handy for plotting.
Details
A common use of this function would be to obtain a plot of the TIF.
Value
A list of:
x
A copy of the argument x
f
A
vector containing the TIF values
Author(s)
Ivailo Partchev
See Also
plot.tif, iif
Examples
plot(trf(Scored2pl))
irtoys documentation built on May 12, 2022, 5:06 p.m.
R Package Documentation
Browse R Packages
We want your feedback!
Note that we can't provide technical support on individual packages. You should contact the package authors for that.
| tif | R Documentation |
Test information function
Description
Returns the test information function (TIF) of the 3PL (1PL, 2PL) model. The TIF is the sum of the item information functions (IIF) in a test, and indicates the precision of measurement that can be achieved with the test at any value of the latent variable, bein inversely related to measurement variance.
Usage
tif(ip, x = NULL)
Arguments
ip |
Item parameters: the output of est. |
x |
The values of the latent variable (θ in the equation above), at which the TIF will be evaluated. If not given, 99 values spaced evenly between -4 and +4 will be used, handy for plotting. |
Details
A common use of this function would be to obtain a plot of the TIF.
Value
A list of:
x |
A copy of the argument |
f |
A vector containing the TIF values |
Author(s)
Ivailo Partchev
See Also
plot.tif, iif
Examples
plot(trf(Scored2pl))
R Package Documentation
Browse R Packages
We want your feedback!
Note that we can't provide technical support on individual packages. You should contact the package authors for that.
Embedding an R snippet on your website
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.