condition mean min max ZT0-3 871.807436 871.807436 871.807436 ZT4-7 831.827638 831.827638 831.827638 ZT8-11 690.8668144999999 690.8668144999999 690.8668144999999 ZT12-15 617.9971015 617.9971015 617.9971015 ZT16-19 791.6719230000001 791.6719230000001 791.6719230000001 ZT20-23 990.9798344999999 990.9798344999999 990.9798344999999