Table 2.
Characteristics of the distribution of salivary cortisol and immunoglobulin A concentrations.
| Variable | Cortisol (nmol/L) | S-IgA (mg/L) | ||||
|---|---|---|---|---|---|---|
| Morning | Afternoon | p | Morning | Afternoon | p | |
| Mean | 19.97 | 8.84 | <0.01 ** | 245.0 | 211.3 | 0.08 |
| Median | 18.76 | 8.28 | <0.01 ** | 204.0 | 189.1 | 0.50 |
| SD | 7.17 | 3.12 | <0.01 ** | 163.7 | 119.4 | 0.03 * |
| CV | 35.9% | 35.3% | 0.90 | 66.8% | 56.5% | 0.17 |
| Q1 | 15.17 | 6.62 | <0.01 ** | 123.5 | 123.7 | 0.94 |
| Q3 | 24.00 | 10.48 | <0.01 ** | 349.4 | 265.7 | 0.02 * |
| IQR | 8.83 | 3.86 | 0.01 * | 225.9 | 142.0 | 0.01 * |
| Skewness | 0.49 | 1.06 | 0.02 * | 1.34 | 1.12 | 0.80 |
| Kurtosis | 2.80 | 4.78 | <0.01 ** | 5.46 | 4.12 | 0.80 |
| JB | 4.7 | 36.1 | 62.3 | 29.5 | ||
| p = 0.10 | p < 0.01 ** | p < 0.01 ** | p < 0.01 ** | |||
S-IgA, secretory immunoglobulin A; SD, standard deviation; CV, coefficient of variation (SD/mean); Q1, quartile 1 (25 percentile); Q3, quartile 3 (75 percentile); IQR, interquartile range (Q3−Q1); skewness, parameter of symmetry; kurtosis, parameter of peak (positive) or flat (negative) distribution. Skewness and kurtosis of a normal distribution are 0 and 3, respectively; JB, Jarque–Bera value. A larger JB value implies that the samples are further from a normal distribution; * p < 0.05 and ** p < 0.01.