condition mean min max ZT0-3 2.620355 2.378815 2.861895 ZT4-7 6.599565 6.599565 6.599565 ZT8-11 13.2626 13.2626 13.2626 ZT12-15 0 0 0 ZT16-19 2.3606 2.3606 2.3606 ZT20-23 2.645055 2.645055 2.645055