condition mean min max ZT0-3 6.882929185 5.223000089 8.542858281 ZT4-7 14.735561597499998 13.679550685 15.791572509999998 ZT8-11 21.69429177 18.611984725 24.776598815 ZT12-15 29.2562022925 28.639254815 29.87314977 ZT16-19 22.840846922500003 20.466636065000003 25.215057780000002 ZT20-23 12.768902098249999 9.7802371065 15.757567089999998