condition mean min max ZT0-3 4.348581666666667 3.22699 6.56655 ZT4-7 7.544465000000001 7.544465000000001 7.544465000000001 ZT8-11 2.915515 2.915515 2.915515 ZT12-15 3.3258525 1.50315 5.148555 ZT16-19 3.47469 3.47469 3.47469 ZT20-23 3.02292 3.02292 3.02292