(a).
| Variables | n | M | Me | Min. | Max. | Q1 | Q3 | R | SD |
|---|---|---|---|---|---|---|---|---|---|
| V_Avg | 40 | 472,75 | 453,60 | 259,16 | 743,87 | 376,28 | 564,13 | 187,85 | 117,25 |
| V_Min | 40 | 128,18 | 130,00 | 0,00 | 360,00 | 80,00 | 185,00 | 105,00 | 78,36 |
| V_Max | 40 | 1093,62 | 1040,00 | 450,00 | 2755,00 | 845,00 | 1255,00 | 410,00 | 411,96 |
| Dif_Avg | 40 | 96,53 | 76,50 | −142,77 | 563,00 | 30,68 | 160,11 | 129,43 | 104,91 |
| Dif_Min | 40 | 55,71 | 55,00 | −50,00 | 180,00 | 20,00 | 85,00 | 65,00 | 46,53 |
| Dif_Max | 40 | 432,69 | 180,00 | −915,00 | 3060,00 | 15,00 | 700,00 | 685,00 | 665,75 |
The following symbols have been used in the table: n, number of samples; M, arithmetic mean; Me, median; Min–max, range of variation; Q1–Q3, first quartile, third quartile; R, interquartile range; SD, standard deviation; V_Avg, average enamel thickness prior to orthodontic treatment; V_Min, minimum enamel thickness prior to orthodontic treatment; V_Max, maximum enamel thickness prior to orthodontic treatment; Dif_Avg, difference in average enamel thickness prior to orthodontic treatment and after its completion; Dif_Min, difference in minimum enamel thickness prior to orthodontic treatment and after its completion; Dif_Max, difference in maximum enamel thickness prior to orthodontic treatment and after its completion.