condition mean min max ZT0-3 15.646834250000001 15.27780643 16.01586207 ZT4-7 6.8075645635 5.9918889415 7.623240185499999 ZT8-11 6.402869355 5.51305645 7.29268226 ZT12-15 7.533394405249999 6.313838179999999 8.752950630499999 ZT16-19 8.239286937500001 7.3544912025 9.1240826725 ZT20-23 13.9653039975 13.42129999 14.509308005