condition mean min max ZT0-3 137.124621 137.124621 137.124621 ZT4-7 130.290517 130.290517 130.290517 ZT8-11 139.627571 139.627571 139.627571 ZT12-15 146.8653595 146.8653595 146.8653595 ZT16-19 169.161091 169.161091 169.161091 ZT20-23 156.196533 156.196533 156.196533