condition mean min max ZT0-3 19.498195 19.498195 19.498195 ZT4-7 17.9405715 17.9405715 17.9405715 ZT8-11 18.8217595 18.8217595 18.8217595 ZT12-15 23.4459715 23.4459715 23.4459715 ZT16-19 19.827014 19.827014 19.827014 ZT20-23 20.7662015 20.7662015 20.7662015