condition mean min max ZT0-3 15.552498765 15.39295474 15.712042789999998 ZT4-7 17.974185379999998 17.496939554999997 18.451431205 ZT8-11 22.6532980175 18.293198235 27.0133978 ZT12-15 20.716316542500003 20.19726414 21.235368945 ZT16-19 21.516253974999998 20.532623455 22.499884495 ZT20-23 20.92247191 20.400875125 21.444068695