mean

To say truth, it is a meane full of uncertainty and danger.

Verily in this treatise this hath been mine only purpose; and the mean to bring the same to effect hath been such as whereby I studied to profit wholesomely, not to please delicately.

Then will not this constitution be a kind of mean between aristocracy and oligarchy?

Of these [rattles] they have Base, Tenor, Countertenor, Meane, and Treble.

Note that (1.41) is simply the probability-weighted mean without any explicit allowance for the stratification; each observation is weighted by its inflation factor and the total divided by the total of the inflation factors for the survey.

...if four numbers be in proportion, the product of the first and last, or of the two extremes, is equal to the product of the second and third, or of the two means.