Find the standard deviation of a vector, matrix, or data.frame. In the latter two cases, return the sd of each column. Unlike the sd function, return NA if there are no observations rather than throw an error.

 models

A general purpose toolbox developed originally for personality, psychometric theory and experimental psychology. Functions are primarily for multivariate analysis and scale construction using factor analysis, principal component analysis, cluster analysis and reliability analysis, although others provide basic descriptive statistics. Item Response Theory is done using factor analysis of tetrachoric and polychoric correlations. Functions for analyzing data at multiple levels include within and between group statistics, including correlations and factor analysis. Validation and cross validation of scales developed using basic machine learning algorithms are provided, as are functions for simulating and testing particular item and test structures. Several functions serve as a useful front end for structural equation modeling. Graphical displays of path diagrams, including mediation models, factor analysis and structural equation models are created using basic graphics. Some of the functions are written to support a book on psychometric theory as well as publications in personality research. For more information, see the <https://personality-project.org/r/> web page.

William Revelle

psych

Procedures for Psychological, Psychometric, and Personality
Research

SD function

<dl> <dt>x</dt>
<dd>a vector, data.frame, or matrix</dd> <dt>na.rm</dt>
<dd>na.rm is assumed to be TRUE</dd></dl>

Arguments

Author

Find the Standard deviation for a vector, matrix, or data.frame - do not return error if there are no cases — SD

<dl>

 <dt>x</dt>
<dd>a vector, data.frame, or matrix</dd>

 <dt>na.rm</dt>
<dd>na.rm is assumed to be TRUE</dd>

</dl>

SD: Find the Standard deviation for a vector, matrix, or data.frame - do not return error if there are no cases

Description

Usage

Value

Arguments

Author

Details

See Also

Examples