The influence of selection of measurement items in several cases of principal component analysis has been discussed by using foot and leg data for footwear planning. The results are as follows:
(1) In the case of the analysis of both foot and leg data, the first and second principal components represent the specific characters concerning both foot and leg and this effect causes the decrease of information concerning the specific character of foot only. Therefore, it is effective to analyze foot and leg separately.
(2) In the analysis, the inclusion of the indices which represent the foot form to analysis items is effective to confirm shape factor of foot under careful examination of index's quality, because it can help the analysis of factor's meaning and increases the contribution rates of the third and fourth principal component.
(3) The exclusion of both items of stature and body weight causes the loss of informations concerning total body mass and decreases the eigenvalues and contribution rates in the first and second principal component of the foot and leg group or in the first principal component of the foot group only. Meanwhile, the exclusion increases the contribution rates of components on foot. Therefore the elimination of both stature and weight is effective to emphasize the shape factor of foot.
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