condition mean min max ZT0-3 16.198866666666667 13.8615 18.3916 ZT4-7 15.8476 15.8476 15.8476 ZT8-11 10.550630000000002 10.550630000000002 10.550630000000002 ZT12-15 13.883025 12.92435 14.8417 ZT16-19 11.815999999999999 11.815999999999999 11.815999999999999 ZT20-23 14.7319 14.7319 14.7319