# psych v1.1.11

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## Procedures for Psychological, Psychometric, and Personality Research

A number of routines for personality, psychometrics and experimental psychology. Functions are primarily for scale construction using factor 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 simulating particular item and test structures are included. Several functions serve as a useful front end for structural equation modeling. Graphical displays of path diagrams, factor analysis and structural equation models are created using basic graphics. Some of the functions are written to support a book on psychometrics as well as publications in personality research. For more information, see the personality-project.org/r webpage.

## Functions in psych

 Name Description principal Principal components analysis cluster.loadings Find item by cluster correlations, corrected for overlap and reliability plot.psych Plotting functions for the psych package of class psych" correct.cor Find dis-attenuated correlations given correlations and reliabilities SD Find the Standard deviation for a vector, matrix, or data.frame - do not return error if there are no cases block.random Create a block randomized structure for n independent variables Yule From a two by two table, find the Yule coefficients of association, convert to phi, or polychoric, recreate table the table to create the Yule coefficient. cities Distances between 11 US cities corr.test Find the correlations, sample sizes, and probability values between elements of a matrix or data.frame. Harman.8 Correlations of eight physical variables (from Harman, 1966) VSS.scree Plot the successive eigen values for a scree test error.crosses Plot x and y error bars bfi 25 Personality items representing 5 factors Dwyer 8 cognitive variables used by Dwyer for an example. cor.smooth Smooth a non-positive definite correlation matrix to make it positive definite winsor Find the Winsorized scores, means, sds or variances for a vector, matrix, or data.frame epi.bfi 13 personality scales from the Eysenck Personality Inventory and Big 5 inventory Tucker 9 Cognitive variables discussed by Tucker and Lewis (1973) make.keys Create a keys matrix for use by score.items or cluster.cor cortest.mat Chi square tests of whether a single matrix is an identity matrix, or a pair of matrices are equal. Gorsuch Example data set from Gorsuch (1997) for an example factor extension. factor.model Find R = F F' + U2 is the basic factor model iclust iclust: Item Cluster Analysis -- Hierarchical cluster analysis using psychometric principles ICC Intraclass Correlations (ICC1, ICC2, ICC3 from Shrout and Fleiss) msq 75 mood items from the Motivational State Questionnaire for 3896 participants blot Bond's Logical Operations Test -- BLOT cosinor Functions for analysis of circadian or diurnal data Schmid 12 variables created by Schmid and Leiman to show the Schmid-Leiman Transformation ICLUST.sort Sort items by absolute size of cluster loadings df2latex Convert a data frame or matrix to a LaTeX table mixed.cor Find correlations for mixtures of continuous, polytomous, and dichotomous variables comorbidity Convert base rates of two diagnoses and their comorbidity into phi, Yule, and tetrachorics vegetables Paired comparison of preferences for 9 vegetables score.irt Find Item Response Theory (IRT) based scores for dichotomous or polytomous items glb.algebraic Find the greatest lower bound to reliability. table2matrix Convert a table with counts to a matrix or data.frame representing those counts. Bechtoldt Seven data sets showing a bifactor solution. phi.demo A simple demonstration of the Pearson, phi, and polychoric corelation sim.item Generate simulated data structures for circumplex or simple structure cluster.fit cluster Fit: fit of the cluster model to a correlation matrix Harman Two data sets from Harman (1967). 9 cognitive variables from Holzinger and 8 emotional variables from Burt VSS.parallel Compare real and random VSS solutions tetrachoric Tetrachoric, polychoric, biserial and polyserial correlations from various types of input cor2dist Convert correlations to distances (necessary to do multidimensional scaling of correlation data) thurstone Thurstone Case V scaling affect Two data sets of affect and arousal scores as a function of personality and movie conditions factor.residuals R* = R- F F' pairs.panels SPLOM, histograms and correlations for a data matrix ICLUST.rgraph Draw an ICLUST graph using the Rgraphviz package factor.congruence Coefficient of factor congruence matrix.addition A function to add two vectors or matrices eigen.loadings Convert eigen vectors and eigen values to the more normal (for psychologists) component loadings sim.VSS create VSS like data factor.rotate Hand" rotate a factor loading matrix bi.bars Draw pairs of bargraphs based on two groups circ.tests Apply four tests of circumplex versus simple structure cushny A data set from Cushny and Peebles (1905) on the effect of three drugs on hours of sleep, used by Student (1908) heights A data.frame of the Galton (1888) height and cubit data set. VSS.plot Plot VSS fits biplot.psych Draw biplots of factor or component scores by factor or component loadings alpha Find two estimates of reliability: Cronbach's alpha and Guttman's Lambda 6. dummy.code Create dummy coded variables cor.plot Create an image plot for a correlation or factor matrix draw.tetra Draw a correlation ellipse and two normal curves to demonstrate tetrachoric correlation factor.fit How well does the factor model fit a correlation matrix. Part of the VSS package interp.median Find the interpolated sample median, quartiles, or specific quantiles for a vector, matrix, or data frame logistic Logistic transform from x to p and logit transform from p to x paired.r Test the difference between (un)paired correlations describe Basic descriptive statistics useful for psychometrics factor2cluster Extract cluster definitions from factor loadings cubits Galton's example of the relationship between height and 'cubit' or forearm length ICLUST.cluster Function to form hierarchical cluster analysis of items fa.sort Sort factor analysis or principal components analysis loadings ICLUST.graph create control code for ICLUST graphical output cluster.cor Find correlations of composite variables from a larger matrix VSS Apply the Very Simple Structure and MAP criteria to determine the appropriate number of factors. fa.diagram Graph factor loading matrices irt.item.diff.rasch Simple function to estimate item difficulties using IRT concepts galton Galton's Mid parent child height data guttman Alternative estimates of test reliabiity 00.psych A package for personality, psychometric, and psychological research irt.fa Item Response Analysis by factor analysis of tetrachoric/polychoric correlations omega Calculate McDonald's omega estimates of general and total factor saturation print.psych Print and summary functions for the psych class omega.graph Graph hierarchical factor structures rescale Function to convert scores to conventional " metrics predict.psych Prediction function for factor analysis or principal components headtail Combine calls to head and tail cluster2keys Convert a cluster vector (from e.g., kmeans) to a keys matrix suitable for scoring item clusters. harmonic.mean Find the harmonic mean of a vector, matrix, or columns of a data.frame burt 11 emotional variables from Burt (1915) structure.diagram Draw a structural equation model specified by two measurement models and a structural model simulation.circ Simulations of circumplex and simple structure read.clipboard shortcut for reading from the clipboard mardia Calculate univariate or multivariate (Mardia's test) skew and kurtosis for a vector, matrix, or data.frame mat.sort Sort the elements of a correlation matrix to reflect factor loadings iqitems 14 multiple choice IQ items error.bars.by Plot means and confidence intervals for multiple groups r.test Tests of significance for correlations tr Find the trace of a square matrix fa.extension Apply Dwyer's factor extension to find factor loadings for extended variables polychor.matrix Phi or Yule coefficient matrix to polychoric coefficient matrix peas Galtons Peas sim.hierarchical Create a population or sample correlation matrix, perhaps with hierarchical structure. error.bars Plot means and confidence intervals multi.hist Multiple histograms with density and normal fits on one page reverse.code Reverse the coding of selected items prior to scale analysis neo NEO correlation matrix from the NEO_PI_R manual sat.act 3 Measures of ability: SATV, SATQ, ACT describe.by Basic summary statistics by group phi2poly Convert a phi coefficient to a polychoric correlation fa.parallel Scree plots of data or correlation matrix compared to random parallel" matrices parcels Find miniscales (parcels) of size 2 or 3 from a set of items cohen.kappa Find Cohen's kappa and weighted kappa coefficients for correlation of two raters scatter.hist Draw a scatter plot with associated X and Y histograms, densitie and correlation score.items Score item composite scales and find Cronbach's alpha, Guttman lambda 6 and item whole correlations sim.structure Create correlation matrices or data matrices with a particular measurement and structural model score.alpha Score scales and find Cronbach's alpha as well as associated statistics fisherz Fisher r to z and z to r and confidence intervals Promax Perform bifactor, promax or targeted rotations and return the inter factor angles. scaling.fits Test the adequacy of simple choice, logistic, or Thurstonian scaling. p.rep Find the probability of replication for an F, t, or r and estimate effect size spider Make "radar" or "spider" plots. sim.congeneric Simulate a congeneric data set income US family income from US census 2008 cta Simulate the C(ues) T(endency) A(ction) model of motivation kaiser Apply the Kaiser normalization when rotating factors factor.scores Various ways to estimate factor scores for the factor analysis model polar Convert Cartesian factor loadings into polar coordinates score.multiple.choice Score multiple choice items and provide basic test statistics test.psych Testing of functions in the psych package factor.stats Find various goodness of fit statistics for factor analysis and principal components rangeCorrection Correct correlations for restriction of range. (Thorndike Case 2) iclust.diagram Draw an ICLUST hierarchical cluster structure diagram fa MinRes (minimum residual) Factor analysis as well as Factor Analysis by Principal Axis, Weighted Least Squares or Maximum Likelihood bock Bock and Liberman (1970) data set of 1000 observations of the LSAT count.pairwise Count number of pairwise cases for a data set with missing (NA) data. ellipses Plot data and 1 and 2 sigma correlation ellipses phi Find the phi coefficient of correlation between two dichotomous variables diagram Helper functions for drawing path model diagrams scrub A utility for basic data cleaning and recoding. Changes values outside of minimum and maximum limits to NA. sim.anova Simulate a 3 way balanced ANOVA or linear model, with or without repeated measures. geometric.mean Find the geometric mean of a vector or columns of a data.frame. cluster.plot Plot factor/cluster loadings and assign items to clusters by their highest loading. cortest.bartlett Bartlett's test that a correlation matrix is an identity matrix sim Functions to simulate psychological/psychometric data. irt.1p Item Response Theory estimate of theta (ability) using a Rasch (like) model set.cor Set Correlation and Multiple Regression from raw or matrix input super.matrix Form a super matrix from two sub matrices. partial.r Find the partial correlations for a set (x) of variables with set (y) removed. smc Find the Squared Multiple Correlation (SMC) of each variable with the remaining variables in a matrix structure.list Create factor model matrices from an input list No Results!