condition mean min max ZT0-3 6.809115 6.63408 6.98415 ZT4-7 6.619285 6.619285 6.619285 ZT8-11 9.052900000000001 9.052900000000001 9.052900000000001 ZT12-15 0 0 0 ZT16-19 9.768640000000001 9.768640000000001 9.768640000000001 ZT20-23 8.4608 8.4608 8.4608