Note that Pearson's original paper was entitled "On Lines and Planes of Closest Fit to Systems of Points in Space" – "in space" implies physical Euclidean space where such concerns do not arise.
但是在Pearson的题为 "On Lines and Planes of Closest Fit to Systems of Points in Space"的原始文件里，是假设在欧几里得空间里不考虑这些。