condition mean min max ZT0-3 16.4091803 14.21709168 18.60126892 ZT4-7 9.1236238345 8.5097422395 9.7375054295 ZT8-11 15.123082173 11.384822331 18.861342014999998 ZT12-15 26.4619119125 20.069476610000002 32.854347215 ZT16-19 19.89651061 19.28085171 20.51216951 ZT20-23 23.996967705 22.127760979999998 25.86617443