In the argument by Paul Garcia:
> Take the set of all projections: they are all forecasts, but with no extra
> dimensions added. But it is possible to produce forecasts which are not
> projections, but based on other stuff (prophecies, gut feeling, etc.). So
> the set of forecasts is bigger than the set of projections and includes all
> the projections. Ergo: projections are a subset of forecasts.
The first statement is not incontrovertible and I, for one, do not agree
with it. Some projections are untenable as forecasts because they are
contradicted by other evidence. If in successive months a baby has 0 ,
1, 2, 3 and 4 teeth, it would be a projection to predict 60 teeth after 5
years but I would not offer it as a forecast.
Thus, as Dave Stewardson already said, neither 'projection' nor
'forecast' is a subset of the other.
Sandy MacRae
StatBasics
6, Ascot Road
Moseley
Birmingham
B13 9EL
Phone / Fax: 0121 247 6138
http://www.statbasics.co.uk
http://www.difftest.co.uk
|