# psych v1.0-42

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## Procedures for Personality and Psychological Research

A number of routines for personality, psychometrics and experimental psychology. Functions are primarily for scale construction, cluster analysis and reliability analysis, although others provide basic descriptive statistics. For more information, see the personality-project.org/r.

## Functions in psych

 Name Description headtail Combine calls to head and tail Yule From a two by two table, find the Yule coefficient, convert to phi, or polychoric, recreate table the table to create the Yule coefficient. omega.graph Graph hierarchical factor structures phi.demo Create demo data for psychometrics psych A package for personality, psychometric, and psychological research ICLUST.sort Sort items by absolute size of cluster loadings ICLUST.cluster Function to form hierarchical cluster analysis of items score.items Score item composite scales and find Cronbach's alpha as well as associated statistics galton Galton's Mid parent child height data VSS.scree Plot a scree test VSS Apply the Very Simple Structure criterion to determine the appropriate number of factors. ellipses Plot data and 1 and 2 sigma correlation ellipses circ.simulation Simulations of circumplex and simple structure error.bars.by Plot means and confidence intervals for multiple groups circ.tests Apply four tests of circumplex versus simple structure paired.r Test the difference between (un)paired correlations mat.regress Multiple Regression from matrix input ICLUST.graph create control code for ICLUST graphical output bfi 25 Personality items representing 5 factors eigen.loadings Convert eigen vectors and eigen values to the more normal (for psychologists) component loadings factor.fit How well does the factor model fit a correlation matrix. Part of the VSS package correct.cor Find dis-attenuated correlations and give alpha reliabilities ICLUST.rgraph Draw an ICLUST graph using the Rgraphviz package cluster.plot Plot factor/cluster loadings and assign items to clusters by their highest loading error.crosses Plot x and y error bars omega Calculate the omega estimate of factor saturation VSS.plot Plot VSS fits VSS.simulate create VSS like data ICLUST ICLUST: Item Cluster Analysis -- Hierarchical cluster analysis using psychometric principles skew Calculate skew for a vector, matrix, or data.frame read.clipboard shortcut for reading from the clipboard VSS.parallel Compare real and random VSS solutions fa.graph Graph factor loading matrices fa.parallel Scree plots of data or correlation matrix compared to random parallel" matrices irt.1p Item Response Theory estimate of theta (ability) using a Rasch (like) model phi Find the phi coefficient of correlation between two dichotomous variables factor.congruence Coefficient of factor congruence score.alpha Score scales and find Cronbach's alpha as well as associated statistics schmid Apply the Schmid Leiman transformation to a correlation matrix cubits Galton's example of the relationship between height and 'cubit' or forearm length harmonic.mean Find the harmonic mean of a vector, matrix, or columns of a data.frame cluster.loadings Find item by cluster correlations, corrected for overlap and reliability alpha.scale Cronbach alpha for a scale count.pairwise Count number of pairwise cases for a data set with missing (NA) data. item.sim Generate simulated data structures for circumplex or simple structure heights A data.frame of the Galton (1888) height and cubit data set. error.bars Plot means and confidence intervals factor.rotate Hand" rotate a factor loading matrix fisherz Fisher r to z and z to r and confidence intervals interp.median Find the interpolated sample median, quartiles, or specific quantiles for a vector, matrix, or data frame factor2cluster Extract cluster definitions from factor loadings factor.model Find R = F F' + U2 is the basic factor model describe Basic descriptive statistics useful for psychometrics factor.pa Principal Axis Factor Analysis geometric.mean Find the geometric mean of a vector or columns of a data.frame. cluster.cor Find correlations of composite variables from a larger matrix polar Convert Cartesian factor loadings into polar coordinates factor.residuals R* = R- F F' polychor.matrix Phi or Yule coefficient matrix to polychoric coefficient matrix sat.act 3 Measures of ability: SATV, SATQ, ACT peas Galtons Peas phi2poly Convert a phi coefficient to a polychoric correlation multi.hist Multiple histograms with density and normal fits on one page irt.item.diff.rasch Simple function to estimate item difficulties using IRT concepts p.rep Find the probability of replication for an F, t, or r and estimate effect size make.hierarchical Create a population or sample correlation matrix with hierachical structure. r.test Tests of significance for correlations poly.mat Find polychoric correlations of item data matrix.addition A function to add two vectors or matrices score.multiple.choice Score multiple choice items and provide basic test statistics winsor Find the Winsorized mean for a vector, matrix, or data.frame table2matrix Convert a table with counts to a matrix or data.frame representing those counts. iqitems 14 multiple choice IQ items principal Principal components analysis test.psych Testing of functions in the psych package kurtosi Kurtosis of a vector, matrix, or data frame cluster.fit cluster Fit: fit of the cluster model to a correlation matrix congeneric.sim Simulate a congeneric data set describe.by Basic summary statistics by group pairs.panels SPLOM, histograms and correlations for a data matrix rescale Function to convert scores to conventional " metrics No Results!