On Thu, 10 Aug 2006 08:09:51 +0100, Guy King
wrote:

Of course. That's why I used the word *average*!

Yeah, but I was pointing out that the range either side of the average
is likely to be so large that the actual value of the average is going
to be of little use as a pointer to how much is to be expected in your
particular case.

I would imagine it is only a tiny percentage of the said terraced
houses that are wasting loads of gas or not using any gas. And the two
extremes found in that tiny percentage, would to a large extent cancel
each other out, no?

Perhaps I should rephrase my question and ask for the mean rather than
the average.

Jake D