At the end of the page they talk about "mean" vrs "average" there does appear to be a difference. What is it?

many thanks, Jerry

Jerry,

The word average is used in everyday language in a non-technical sense so statisticians use the word mean rather than average so that we know they have the technical meaning in mind. The word average however is still used at times by statisticians with precisely the same meaning as mean. I think that is what is going on the the page you sent us where the table at the end has both words mean and average. Both words have the same meaning.

Harley