# psych v1.7.8

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## Procedures for Psychological, Psychometric, and Personality Research

A general purpose toolbox 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. Functions for simulating and testing 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 psychometric theory as well as publications in personality research. For more information, see the <http://personality-project.org/r> web page.

## Functions in psych

 Name Description 00.psych A package for personality, psychometric, and psychological research Gleser Example data from Gleser, Cronbach and Rajaratnam (1965) to show basic principles of generalizability theory. ICLUST.cluster Function to form hierarchical cluster analysis of items ICLUST.graph create control code for ICLUST graphical output ICC Intraclass Correlations (ICC1, ICC2, ICC3 from Shrout and Fleiss) iclust iclust: Item Cluster Analysis -- Hierarchical cluster analysis using psychometric principles ICLUST.rgraph Draw an ICLUST graph using the Rgraphviz package ICLUST.sort Sort items by absolute size of cluster loadings Gorsuch Example data set from Gorsuch (1997) for an example factor extension. Harman Five data sets from Harman (1967). 9 cognitive variables from Holzinger and 8 emotional variables from Burt VSS Apply the Very Simple Structure, MAP, and other criteria to determine the appropriate number of factors. VSS.parallel Compare real and random VSS solutions Schutz The Schutz correlation matrix example from Shapiro and ten Berge Tucker 9 Cognitive variables discussed by Tucker and Lewis (1973) bestScales A set of functions for factorial and empirical scale construction bfi 25 Personality items representing 5 factors SD Find the Standard deviation for a vector, matrix, or data.frame - do not return error if there are no cases Schmid 12 variables created by Schmid and Leiman to show the Schmid-Leiman Transformation bi.bars Draw pairs of bargraphs based on two groups Bechtoldt Seven data sets showing a bifactor solution. KMO Find the Kaiser, Meyer, Olkin Measure of Sampling Adequacy Promax Perform bifactor, promax or targeted rotations and return the inter factor angles. affect Two data sets of affect and arousal scores as a function of personality and movie conditions alpha Find two estimates of reliability: Cronbach's alpha and Guttman's Lambda 6. cluster.fit cluster Fit: fit of the cluster model to a correlation matrix cluster.loadings Find item by cluster correlations, corrected for overlap and reliability cluster.plot Plot factor/cluster loadings and assign items to clusters by their highest loading. cluster2keys Convert a cluster vector (from e.g., kmeans) to a keys matrix suitable for scoring item clusters. corr.test Find the correlations, sample sizes, and probability values between elements of a matrix or data.frame. biplot.psych Draw biplots of factor or component scores by factor or component loadings blant A 29 x 29 matrix that produces weird factor analytic results bock Bock and Liberman (1970) data set of 1000 observations of the LSAT correct.cor Find dis-attenuated correlations given correlations and reliabilities Dwyer 8 cognitive variables used by Dwyer for an example. eigen.loadings Convert eigen vectors and eigen values to the more normal (for psychologists) component loadings VSS.plot Plot VSS fits VSS.scree Plot the successive eigen values for a scree test Yule From a two by two table, find the Yule coefficients of association, convert to phi, or tetrachoric, recreate table the table to create the Yule coefficient. burt 11 emotional variables from Burt (1915) cor2dist Convert correlations to distances (necessary to do multidimensional scaling of correlation data) corFiml Find a Full Information Maximum Likelihood (FIML) correlation or covariance matrix from a data matrix with missing data ability 16 ability items scored as correct or incorrect. block.random Create a block randomized structure for n independent variables blot Bond's Logical Operations Test -- BLOT cohen.d Find Cohen d and confidence intervals cattell 12 cognitive variables from Cattell (1963) circ.tests Apply four tests of circumplex versus simple structure cor.smooth Smooth a non-positive definite correlation matrix to make it positive definite cor.wt The sample size weighted correlation may be used in correlating aggregated data cta Simulate the C(ues) T(endency) A(ction) model of motivation comorbidity Convert base rates of two diagnoses and their comorbidity into phi, Yule, and tetrachorics cushny A data set from Cushny and Peebles (1905) on the effect of three drugs on hours of sleep, used by Student (1908) densityBy Create a 'violin plot' or density plot of the distribution of a set of variables fa.poly Deprecated Exploratory Factor analysis functions. Please use fa cubits Galton's example of the relationship between height and 'cubit' or forearm length dfOrder Sort (order) a dataframe or matrix by multiple columns diagram Helper functions for drawing path model diagrams ellipses Plot data and 1 and 2 sigma correlation ellipses epi Eysenck Personality Inventory (EPI) data for 3570 participants cities Distances between 11 US cities scoreOverlap Find correlations of composite variables (corrected for overlap) from a larger matrix. cor.ci Bootstrapped confidence intervals for raw and composite correlations epi.bfi 13 personality scales from the Eysenck Personality Inventory and Big 5 inventory error.bars Plot means and confidence intervals fa.sort Sort factor analysis or principal components analysis loadings fa.multi Multi level (hierarchical) factor analysis factor.stats Find various goodness of fit statistics for factor analysis and principal components factor2cluster Extract cluster definitions from factor loadings interp.median Find the interpolated sample median, quartiles, or specific quantiles for a vector, matrix, or data frame iqitems 16 multiple choice IQ items cosinor Functions for analysis of circadian or diurnal data count.pairwise Count number of pairwise cases for a data set with missing (NA) data. draw.tetra Draw a correlation ellipse and two normal curves to demonstrate tetrachoric correlation dummy.code Create dummy coded variables logistic Logistic transform from x to p and logit transform from p to x lowerUpper Combine two square matrices to have a lower off diagonal for one, upper off diagonal for the other msq 75 mood items from the Motivational State Questionnaire for 3896 participants mssd Find von Neuman's Mean Square of Successive Differences cor.plot Create an image plot for a correlation or factor matrix cortest.bartlett Bartlett's test that a correlation matrix is an identity matrix cortest.mat Chi square tests of whether a single matrix is an identity matrix, or a pair of matrices are equal. describeBy Basic summary statistics by group describe Basic descriptive statistics useful for psychometrics error.bars.by Plot means and confidence intervals for multiple groups errorCircles Two way plots of means, error bars, and sample sizes fa.parallel Scree plots of data or correlation matrix compared to random parallel" matrices esem Perform and Exploratory Structural Equation Model (ESEM) by using factor extension techniques fa Exploratory Factor analysis using MinRes (minimum residual) as well as EFA by Principal Axis, Weighted Least Squares or Maximum Likelihood fa.diagram Graph factor loading matrices fa.extension Apply Dwyer's factor extension to find factor loadings for extended variables factor.model Find R = F F' + U2 is the basic factor model factor.residuals R* = R- F F' geometric.mean Find the geometric mean of a vector or columns of a data.frame. glb.algebraic Find the greatest lower bound to reliability. iclust.diagram Draw an ICLUST hierarchical cluster structure diagram fa.random A first approximation to Random Effects Exploratory Factor Analysis partial.r Find the partial correlations for a set (x) of variables with set (y) removed. peas Galtons Peas rescale Function to convert scores to conventional " metrics residuals.psych Extract residuals from various psych objects splitHalf Alternative estimates of test reliabiity harmonic.mean Find the harmonic mean of a vector, matrix, or columns of a data.frame headTail Combine calls to head and tail heights A data.frame of the Galton (1888) height and cubit data set. factor.rotate Hand" rotate a factor loading matrix factor.scores Various ways to estimate factor scores for the factor analysis model irt.fa Item Response Analysis by Exploratory Factor Analysis of tetrachoric/polychoric correlations make.keys Create a keys matrix for use by score.items or cluster.cor mat.sort Sort the elements of a correlation matrix to reflect factor loadings omega.graph Graph hierarchical factor structures outlier Find and graph Mahalanobis squared distances to detect outliers polar Convert Cartesian factor loadings into polar coordinates polychor.matrix Phi or Yule coefficient matrix to polychoric coefficient matrix rangeCorrection Correct correlations for restriction of range. (Thorndike Case 2) read.file Shortcuts for reading from the clipboard or a file irt.item.diff.rasch Simple function to estimate item difficulties using IRT concepts matrix.addition A function to add two vectors or matrices mediate Estimate and display direct and indirect effects of mediators and moderator in path models df2latex Convert a data frame, correlation matrix, or factor analysis output to a LaTeX table error.crosses Plot x and y error bars error.dots Show a dot.chart with error bars for different groups or variables factor.congruence Coefficient of factor congruence factor.fit How well does the factor model fit a correlation matrix. Part of the VSS package income US family income from US census 2008 kaiser Apply the Kaiser normalization when rotating factors cohen.kappa Find Cohen's kappa and weighted kappa coefficients for correlation of two raters neo NEO correlation matrix from the NEO_PI_R manual fisherz Transformations of r, d, and t including Fisher r to z and z to r and confidence intervals galton Galton's Mid parent child height data irt.1p Item Response Theory estimate of theta (ability) using a Rasch (like) model multi.hist Multiple histograms with density and normal fits on one page multilevel.reliability Find and plot various reliability/gneralizability coefficients for multilevel data phi2tetra Convert a phi coefficient to a tetrachoric correlation plot.psych Plotting functions for the psych package of class psych" scoreIrt Find Item Response Theory (IRT) based scores for dichotomous or polytomous items scoreItems Score item composite scales and find Cronbach's alpha, Guttman lambda 6 and item whole correlations mardia Calculate univariate or multivariate (Mardia's test) skew and kurtosis for a vector, matrix, or data.frame omega Calculate McDonald's omega estimates of general and total factor saturation pairs.panels SPLOM, histograms and correlations for a data matrix parcels Find miniscales (parcels) of size 2 or 3 from a set of items print.psych Print and summary functions for the psych class schmid Apply the Schmid Leiman transformation to a correlation matrix score.alpha Score scales and find Cronbach's alpha as well as associated statistics sim.item Generate simulated data structures for circumplex, spherical, or simple structure r.test Tests of significance for correlations setCor Set Correlation and Multiple Regression from matrix or raw input sim Functions to simulate psychological/psychometric data. sim.structure Create correlation matrices or data matrices with a particular measurement and structural model simulation.circ Simulations of circumplex and simple structure test.psych Testing of functions in the psych package tetrachoric Tetrachoric, polychoric, biserial and polyserial correlations from various types of input unidim Several indices of the unidimensionality of a set of variables. irt.responses Plot probability of multiple choice responses as a function of a latent trait psych.misc Miscellaneous helper functions for the psych package mixedCor Find correlations for mixtures of continuous, polytomous, and dichotomous variables sim.multilevel Simulate multilevel data with specified within group and between group correlations table2matrix Convert a table with counts to a matrix or data.frame representing those counts. test.irt A simple demonstration (and test) of various IRT scoring algorthims. thurstone Thurstone Case V scaling smc Find the Squared Multiple Correlation (SMC) of each variable with the remaining variables in a matrix statsBy Find statistics (including correlations) within and between groups for basic multilevel analyses structure.diagram Draw a structural equation model specified by two measurement models and a structural model winsor Find the Winsorized scores, means, sds or variances for a vector, matrix, or data.frame predict.psych Prediction function for factor analysis or principal components principal Principal components analysis (PCA) score.multiple.choice Score multiple choice items and provide basic test statistics scrub A utility for basic data cleaning and recoding. Changes values outside of minimum and maximum limits to NA. vegetables Paired comparison of preferences for 9 vegetables sim.congeneric Simulate a congeneric data set sim.hierarchical Create a population or sample correlation matrix, perhaps with hierarchical structure. spi A sample from the SAPA Personality Inventory including an item dictionary and scoring keys. spider Make "radar" or "spider" plots. tr Find the trace of a square matrix withinBetween An example of the distinction between within group and between group correlations p.rep Find the probability of replication for an F, t, or r and estimate effect size paired.r Test the difference between (un)paired correlations phi Find the phi coefficient of correlation between two dichotomous variables phi.demo A simple demonstration of the Pearson, phi, and polychoric corelation reverse.code Reverse the coding of selected items prior to scale analysis sat.act 3 Measures of ability: SATV, SATQ, ACT scaling.fits Test the adequacy of simple choice, logistic, or Thurstonian scaling. scatterHist Draw a scatter plot with associated X and Y histograms, densities and correlation sim.VSS create VSS like data sim.anova Simulate a 3 way balanced ANOVA or linear model, with or without repeated measures. structure.list Create factor model matrices from an input list superMatrix Form a super matrix from two sub matrices. 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