TABLE 2
FROM:
Forecasting and evaluating the tourist hotel industry performance in Taiwan based on Grey theory
Wann-Yih Wu, Shih-Wen Hsiao and Cheng-Hung Tsai
BACK TO ARTICLETable 2. The grades of forecasting accuracy
| Residual error test | Post-error test | |||
|---|---|---|---|---|
| Grade | e(k) 1 | Grade | P 2 | C 3 |
| Useful | 1- e(k) | Good | >0.95 | <0.35 |
 90%
| Qualified | >0.8 | <0.5 | |
| Just the mark | >0.7 | <0.65 | ||
| Useless | 1- e(k)<90% | Unqualified |  0.7 | 0.65 |
1
e(k)=|x
(0)(k)-
(0)(k)/x
(0)(k)| 
100%
.
2 P =Prob.{|q(k)|<0.6745S 1}.
3 C =S 2/S 1.
