Sometimes different terminology is used that we aren’t used to. One example I’ve come across is finding the Average grade/slope of a surface. If we look in the Surface Properties we don’t see a listing for the Average grade/slope of a surface.
But if you take a look at the highlighted row we see we are provided with the Mean grade/slope. Mean is synonymous with Average. If you sit down and do the math you find that it’s the weighted average slope of the surface. For the surface above the unweighted average is 2.713%.