condition mean min max ZT0-3 15.264065 15.264065 15.264065 ZT4-7 15.096595 15.096595 15.096595 ZT8-11 18.174575 18.174575 18.174575 ZT12-15 18.744916666666665 18.744916666666665 18.744916666666665 ZT16-19 14.38497 14.38497 14.38497 ZT20-23 14.040397500000001 14.040397500000001 14.040397500000001