condition mean min max ZT0-3 22.14688333333333 15.13775 26.86995 ZT4-7 7.149290000000001 7.149290000000001 7.149290000000001 ZT8-11 6.883885 6.883885 6.883885 ZT12-15 11.381630000000001 9.95776 12.8055 ZT16-19 14.693850000000001 14.693850000000001 14.693850000000001 ZT20-23 22.90745 22.90745 22.90745