Which forecasting method forms a forecast by weighting the most recent data $($in time$)$ more

highly than less recent data?

Regarding quantitative forecasting, what are the main differences between an intuitive method

and a formal statistical model?

Which measure of forecast accuracy should be used in the following situations?

$($i$)$ A small number of large forecast errors needs to be guarded against.

$($ii$)$ Errors need to be measured in percentage terms.

$($iii$)$ Whether a model's forecasts are biased is more important than the typical size of errors.