condition mean min max ZT0-3 0.444731 0.444731 0.444731 ZT4-7 0.350901 0.350901 0.350901 ZT8-11 0.3383385 0.3383385 0.3383385 ZT12-15 0.5634025 0.5634025 0.5634025 ZT16-19 0.475047 0.475047 0.475047 ZT20-23 0.512866 0.512866 0.512866