The standard deviation is a measure that indicates the extent to which the peaks and troughs of a wave differ on average from the mean voltage. A large standard deviation is a measure of large amplitude waves, i.e., on average the peaks and troughs differ by a large extent from the mean voltage.
The weighted average formula is used to calculate the average value of a particular set of numbers with different levels of relevance. The relevance of each number is called its weight. The weights should be represented as a percentage of the total relevancy. Therefore, all weights should be equal to 100%, or 1.
A weighted average is a more accurate measurement of scores or investments that are of relative importance to each other. This is often the case with investment portfolios, grade scoring and other statistics. You can find out how to calculate weighted averages.