In article ,
Janet Baraclough wrote:

Some 17C houses had no foundations, or were built of materials
designed to sag and move. I don't think a single observation can count
as evidence..so I've heard :-)

Yes, but this wasn't one such.

And you heard wrong :-) A single observation is a proof that the
observed effect is possible; under some circumstances, it can be
enough for a statistical estimate of likelihood (a damn poor one,
I admit, but one nevertheless).


Regards,
Nick Maclaren.