The Normal Region –- a Multivariate Problem

The multivariate 0.95 region of 5 variates relevant to the metabolism of hemoglobin was estimated from observations made in healthy adult males and females. The multivariate Gaussian distribution was used as a model and found to be valid. The study revealed that highly abnormal combinations might comprise values which were all normal when evaluated separately. Conversely, several variates might have abnormal values in the latter sense, although the corresponding 5 component combination of values was quite normal.