a) The principal factor analysis affords a univariate
explanation of the data variance related to the FHR variability features ASTV
and ALTV, whereas the principal component analysis affords an explanation
requiring three components. Also check the scree plots.
b) The pc-score plots of the factor analysis solution afford
an interpretation of the Apgar index. For this purpose, use the varimax
rotation and plot the categorised data using three classes for the Apgar at 1
minute after birth (Apgar1: ≤5; >5 and ≤8; >8) and two
classes for the Apgar at 5 minutes after birth (Apgar5: ≤8; >8).