Mahalanobis' DistanceUnit space is a data set used as a base. In Quality Engineering , unit space is data set of normal condition or good production. Data set not including unit space is signal space.
The categories, "unit space" and "signal space", are Y of MT method.
The strong point of MT method is that it explains abnormality in a mathematical way.
Usually, Normal condition is explained by normal distribution. But abnormal condition is diffcult to expalain by a shape of distribution. So unit space is the idea to avoid this difficulty.
The quantity of abnormality is expalined by the distance of the average of normal condition (the center position of unit space).
I think the naming of "Unit Space" is inappropriate. I can not understand the meaning of unit space by the name.
"Unit" means "Base" or "Standard". And "Space" means "Distribution" or "Area".
