condition mean min max ZT0-3 3.5674161945000002 2.9544225060000002 4.180409883 ZT4-7 3.9217947415 3.7646749335000003 4.078914549499999 ZT8-11 3.47617195275 3.289839858 3.6625040475 ZT12-15 5.706824951750001 4.063089568500001 7.350560335 ZT16-19 8.069549544000001 7.945423859 8.193675229 ZT20-23 9.741620052750001 9.166676344 10.3165637615