Sweating the Small Stuff: Does data cleaning and testing ... - Frontiers

Sheng and ShengEffect of non-normality on coefficient alpha% rep - number of replications% tbcd - coefficients for generating normal/nonnormal true score% distributions using power method polynomials% ebcd - coefficients for generating normal/nonnormal error score% distributions using power method polynomials%tvar=evar*rho/((1-rho)*k);t=rfsimu(tbcd,n,1,5,tvar);e=rfsimu(ebcd,n,k,0,evar);xn=t*ones(1,k)+e;x=round(xn);alp=k/(k-1)*(1-sum(var(x,1))/var(sum(x,2),1));function X=rfsimu(bcd,n,k,mean,var)%% rfsimu - generate normal/nonnormal distributions using 5-th order power% method polynomials%% X=rfsimu(bcd,n,k,mean,var)%% returns samples of size n by k drawn from a distribution with the desired% moments.%% The INPUT arguments:% bcd - coefficients for generating normal/nonnormal distributions using% the 5-th order polynomials% k - test length% evar - error variance% rho - population reliability% rep - number of replications% tbcd - coefficients for generating normal/nonnormal true score% distributions using power method polynomials% ebcd - coefficients for generating normal/nonnormal error score% distributions using power method polynomials%Z=randn(n,k);Y=bcd(1)+bcd(2)*Z+bcd(3)*Z.ˆ2+bcd(4)*Z.ˆ3+bcd(5)*Z.ˆ4+bcd(6)*Z.ˆ5;X=mean+sqrt(var)*Y;www.frontiersin.org February 2012 | Volume 3 | Article 34 | 40