condition mean min max ZT0-3 1.808605 1.808605 1.808605 ZT4-7 1.143065 1.143065 1.143065 ZT8-11 0.833153 0.833153 0.833153 ZT12-15 0.8173824999999999 0.8173824999999999 0.8173824999999999 ZT16-19 1.250225 1.250225 1.250225 ZT20-23 1.33287 1.33287 1.33287