Adds a new number (giving it an appropriate weight) to the average.
Resets the average incremental instance.
Returns the standard deviation, a measure of the spread of a distribution to quantify the amount of variation or dispersion of a set of data values.
Computes the variance, a measure of the spread of a distribution to quantify how far a set of data values is spread out.
Calculates the average using an accumulative technique (i.e, not all the values are provided at once). The struct doesn't store any previous values.