Table 4. Comparison (Chi-square and Binomial tests) between the amount of scraping (SCRA) behaviors in MARK and SHAM conditions: The frequency of SCRA behavior towards both left and right cheeks is reported in the two conditions (SHAM and MARK 1, 2).
There was a significant increase of SCRA towards both sides of the face under MARK 1 condition compared to SHAM condition in three out of four horses. One out of four horses performed SCRA behavior at higher frequency in MARK 2 compared to SHAM condition. The table also shows the SCRA activity performed only towards the left cheek which corresponded to the mark side (MARK 1, left), with the same three horses showing a significant increase of SCRA in MARK 1 compared to the SHAM condition (left). Regarding the SCRA events towards the right cheek (MARK 2, right), there was no difference in SCRA directed to the right cheek between MARK 2 (right) and SHAM condition (right).
| MARK 1 (left and right)* |
SHAM (left and right)* |
Chi Square (Binomial test)§ | |
| Julia | 64 | 13 | p < 0.0001; χ2 = 32.46 (p < 0.0001; z = 5.7) |
| Calippo | 9 | 7 | p = 0.8065; χ2 = 0.06 (p = 0.8036; z = 0.25) |
| Gina | 30 | 11 | p = 0.0049; χ2 = 7.9 (p = 0.0043; z = 2.81) |
| Betsie | 18 | 7 | p = 0.0455; χ2 = 4 (p = 0.0433; z = 2) |
| MARK 2 (left and right)* |
SHAM (left and right)* |
Chi Square (Binomial test)§ | |
| Julia | 18 | 13 | p = 0.4708; χ2 = 0.52 (p = 0.4731; z = 0.72) |
| Calippo | 13 | 7 | p = 0.2636; χ2 = 1.25 (p = 0.2632; z = 1.12) |
| Gina | 16 | 11 | p = 0.4386; χ2 = 0.6 (p = 0.4421; z = 0.77) |
| Betsie | 21 | 7 | p = 0.014; χ2 = 6.04 (p = 0.0125; z = 2.46) |
| MARK 1 (left)# |
SHAM (left)# |
Chi Square (Binomial test)§ | |
| Julia | 41 | 8 | p < 0.0001; χ2 = 20.9 (p < 0.0001; z = 4.57) |
| Calippo | 6 | 6 | p = 1; χ2 = 0 (p = 1; z = 0) |
| Gina | 16 | 5 | p = 0.0291; χ2 = 4.76 (p = 0.0266; z = 2.18) |
| Betsie | 8 | 1 | p = 0.0455; χ2 = 4 (p = 0.0391; z = n.a.) |
| MARK 2 (right)# |
SHAM (right)# |
Chi Square (Binomial test)§ | |
| Julia | 8 | 5 | p = 0.5839; χ2 = 0.3 (p = 0.5811; z = 0.55) |
| Calippo | 6 | 1 | p = 0.1311; χ2 = 2.28 (p = 0.125; z = n.a.) |
| Gina | 6 | 6 | p = 1; χ2 = 0 (p = 1; z = 0) |
| Betsie | 8 | 6 | p = 0.7773; χ2 = 0.08 (p = 0.7905; z = 0.27) |
* The total of SCRA behaviors directed to both cheeks of the face (left + right) in MARK 1 vs SHAM and MARK 2 vs SHAM
# The total of SCRA behaviors directed to the left cheek (MARK 1 vs SHAM left) or the right cheek (MARK 2 vs SHAM right)
§ Chi-Square "Goodness of Fit" Test and Binomial test (between brackets). Binomial test has been included because two comparisons have expected frequencies lower than 5.0