Table 1. Preference Index calculations.
| Test Number (tn) | STEP 1 | STEP 2 | STEP 3 | STEP 4 | STEP 5 | STEP 6 | STEP 7 |
|---|---|---|---|---|---|---|---|
| Raw Frequency (RF)1 | Cumulative frequency2 | Area3 | Cumulative area4 | Expected Area5 (ExA) | Variation of cumulative area from the ExA6 | Preference Index (PI)7 | |
| 1 | 9 | 9 | 4.5 | 4.5 | 12.4 | −7.9 | −7.9 |
| 2 | 57 | 66 | 85.5 | 90.0 | 55.5 | 34.5 | 26.6 |
| 3 | 28 | 94 | 70.0 | 160.0 | 113.6 | 46.4 | 73.0 |
| 4 | 56 | 150 | 196.0 | 356.0 | 208.1 | 147.9 | 220.9 |
| 5 | 72 | 222 | 324.0 | 680.0 | 326.3 | 353.8 | 574.6 |
| 6 | 59 | 281 | 324.5 | 1004.5 | 451.4 | 553.1 | 1127.8 |
| 7 | 77 | 358 | 500.5 | 1505.0 | 607.4 | 897.6 | 2025.4 |
| 8 | 79 | 437 | 592.5 | 2097.5 | 785.5 | 1312.0 | 3337.4 |
| 9 | 99 | 536 | 841.5 | 2939.0 | 1023.5 | 1915.5 | 5252.9 |
| 10 | 99 | 635 | 940.5 | 3879.5 | 1301.4 | 2578.1 | 7831.0 |
This procedure is carried out for each colour. Example extracted from fish 1, yellow colour.
1Frequencies obtained in each test.
2
.
3Areas calculated as shown in Fig. 2.
4
.
5Mean of cumulative areas from each colour in the respective test number and fish. In this table, we show data only for the yellow colour; the ExA is calculated from data of all tested colours at tn for fish 1.
6Data from Step 4–Step 5.
7Cumulative data of Step 6.