condition mean min max ZT0-3 4.086561666666666 2.11841 5.24198 ZT4-7 1.4190325000000001 1.4190325000000001 1.4190325000000001 ZT8-11 2.6827199999999998 2.6827199999999998 2.6827199999999998 ZT12-15 4.5136725 4.24549 4.781855 ZT16-19 5.65574 5.65574 5.65574 ZT20-23 6.61116 6.61116 6.61116