[justlurking]

Half of the 20th century temps were above average. Half were below average. That's what "average" means.

No, that's a median.

Here's an example using this series of numbers: 1,2,3,4,5,100,101.

The median is 4.
The mean/average is the sum (216) divided by 7 = 30.86.

[Mrs. Don-o]

Not to be to-o-o-o picky, but I think there are three kinds of averages: mean, median, and mode. So if we agree that when "half are above, half are below" it's the "median", it's still a type of average.

Dictionary.com (LINK) defines "mean" as an average, and then says, "Two other common forms of averages are the median and mode."

Though a lot of people do use "average" to mean "arithmetic mean" only.