I'm using R's
factanal function for factor analysis. I know from reading that there are various ways of picking how many factors to use in the analysis. I don't know which to choose, or how to do any of them.
Here's the data I have so far from
factanal. I don't understand what SS loadings are, or why degrees_of_freedom is not = min(#rows,#columns) - #factors.
Just judging from the Cumulative Var, which I think I understand, I would guess that 2 is the right number of factors, but am I right? And if so, how can I convince others that this is the right number of factors?
factanal(x = charges[3:8], factors = 1) # Factor1 # SS loadings 4.779 # Proportion Var 0.797
Test of the hypothesis that 1 factor is sufficient. The chi square statistic is 279.13 on 9 degrees of freedom. The p-value is 6.9e-55
factanal(x = charges[3:8], factors = 2, scores = "regression") # Factor1 Factor2 # SS loadings 2.817 2.544 # Proportion Var 0.470 0.424 # Cumulative Var 0.470 0.894
Test of the hypothesis that 2 factors are sufficient. The chi square statistic is 77.1 on 4 degrees of freedom. The p-value is 7.15e-16
factanal(x = charges[3:8], factors = 3) # Factor1 Factor2 Factor3 # SS loadings 2.769 2.618 0.063 # Proportion Var 0.461 0.436 0.010 # Cumulative Var 0.461 0.898 0.908
The degrees of freedom for the model is 0 and the fit was 0.1047