condition mean min max ZT0-3 1.653535 1.653535 1.653535 ZT4-7 1.6612749999999998 1.6612749999999998 1.6612749999999998 ZT8-11 2.2901949999999998 2.2901949999999998 2.2901949999999998 ZT12-15 1.98222 1.98222 1.98222 ZT16-19 2.16014 2.16014 2.16014 ZT20-23 1.8344999999999998 1.8344999999999998 1.8344999999999998