Average?
Average?
OK, let's assign values to the grades - A1=1, A2=2, B1=3, B2=4.
Take all the grades of all the QFIs and add them up, then divide by the total number of QFIs; this will give you the mean. Above that = above mean , and below it = below mean . If the mean is 1.9, an A2 QFI is below mean compared to the whole population of QFIs, but he could, of course, be considered above mean when compared with other A2 QFIs! Someone who actually avoids flying, or any contact with students, may correctly be described as 'no mean QFI!', which might explain some of the promotions we have all seen over the years.
The Median is the middle value in order. In this example, the Median is 2.5. Even if the statistical mean is 1.9, an A2 instructor is an above Median instructor.
The other statistical value to look at is the Mode. This is the value that occurs with the highest frequency. So, if there are 30 QFIs in total, of which 10xB2, 9xB1, 7xA2 and 4xA1, then everyone who is B1 or above is an above Mode QFI.
In practice, all 3 statistical measures are described (particularly by the media) as average, depending on what point someone is trying to make. So there are lies, damned lies and ... you know the rest.
I'll get my coat ...
STH