What is weighted average atomic number

The Dow Jones Industrial average is a price weighted index.

You can't convert an unweighted average into a weighted average simply by adding something. You have to do the whole calculation for the weighted average.

in weighted average method we assigns the weight to the averages while in average methods we dnt do this

weighted average is an average in which each quantity to be averaged is assigned a weight. These weightings determine the relative importance of each quantity on the average.