Hi Listers,
Below is a syntax to test significant difference between two independent cronbach alphas. I appreciate if someone would modify to allow the testing with the following are already available: cronbach alphas, a1 and a2; number of items (I_1, I_2); sample size(n1, and n2). Please tell me if more info are needed.
DEFINE HWALPHA (!positional !token(3)).
MATRIX.
get mat/variables = !1/missing = omit.
compute alpha = mat(:,1).
compute n=mat(:,2).
compute j=mat(:,3).
compute df = nrow(mat)-1.
compute a = ((j-1)&*((9*n-11)&**2))/((18*j)&*(n-1)).
compute top = a&*((1-alpha)&**(-1/3)).
compute bot = a&*((1-alpha)&**(-2/3)).
compute m = csum(a)-((csum(top)**2)/csum(bot)).
print/title = "** SIGNIFICANCE TEST OF THE DIFFERENCE BETWEEN INDEPENDENT ALPHA COEFFICIENTS **".
print/title = "From Hakstian & Whalen (1976), Psychometrika, 41, 219-231.".
print mat/clabels = "ALPHA" "N" "ITEMS"/title = " "/format F10.4.
compute p = 1-chicdf(m,df).
compute res = {m, df, p}.
print res/clabels = "CHISQ" "DF" "P-VALUE"/title = " "/format F10.4.
END MATRIX.
!END DEFINE.
Thank you in advance.
Jims
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