| Abstract: | Summary This paper is an exposition about the model and techniques in factor analysis, a method of studying the covariance matrix of several properties on the basis of a sample co-variance matrix of independent observations on n individuals. The indeterminacy of the basis of the so called factor space and several possibilities of interpretation are discussed. The scale invariant maximum likelihood estimation of the parameters of the assumed normal distribution which also provides a test on the dimension of the factor space is compared with the customary but unjustified attack of the estimation problem by means of component analysis or modifications of it. The prohibitive slowness of convergence of iterative procedures recommended till now can be removed by steepest ascent methods together with Aitken's acceleration method. An estimate of the original observations according to the model assumed, as to be compared with the data, is given. |
