Since each date is really just a number stored in Excel, to compute the midpoint of two dates you would use the same mathematical formulas you would use to calculate the midpoint of two numbers ...

The midpoint formula seems much more complicated, but when used in a price-demand calculation, allows for the same coefficient of elasticity regardless of whether the price is going up or going down.

The median is the middle number in a sorted ascending or descending list. It can be more descriptive of the dataset than the average. It’s quite different from the mean.

Formula of Mean: Know to How to Calculate Median for Grouped, Ungrouped data along with solved examples, questions with solution.