Material | N c | Average (standard deviation)d | Median (interquartile range)d |
---|---|---|---|
Straw | 61 | 5.64 (1.74) | 6 (2) |
Newspaper | 61 | 5.44 (1.55) | 6 (3) |
Hay | 37 | 5.21 (1.82) | 6 (3) |
Cardboard or paper sacks | 46 | 5.13 (1.58) | 5 (2) |
Chain | 58 | 4.75 (1.79) | 5 (3) |
Unprocessed, fresh wooda | 47 | 4.63 (1.81) | 5 (3) |
Sawdust/wood shavings | 52 | 4.57 (1.94) | 5 (4) |
Rope | 45 | 4.41 (1.64) | 5 (2) |
Peat | 29 | 4.37 (2.08) | 4.5 (3) |
Ball or other object attached to a chain | 47 | 4.31 (1.78) | 4 (3) |
Processed, dry woodb | 34 | 3.89 (1.91) | 4 (4) |
Ball or other object loose on the floor | 53 | 3.71 (1.72) | 4 (3) |
Commercial pig toy | 39 | 3.68 (1.51) | 4 (2) |