How is an average mass different from a weighted average mass?

Answer 1

Weighted means there is a percent abundance given to each constituent isotope.

Answer 2

Suppose you are computing an average for a number of type of masses. They might be isotopes in this case. A weighted average would take into account how much of each isotope is there. A "plain" average would just be an average mass for the various n types. (i.e., add them up and divide by n)

Answer 3

what you mean by N type?

Answer 4

N, as in number of constituents, ie, the number of isotopes in the natural element.

Answer 5

N is the number of types of things or substances you are averaging. In the case of an isotope mixture of an element, it would be the number of isotopes