condition mean min max ZT0-3 3.072635 0.88598 6.42775 ZT4-7 1.733845 1.733845 1.733845 ZT8-11 6.372705 6.372705 6.372705 ZT12-15 3.7487325 2.7860500000000004 4.711415 ZT16-19 5.98233 5.98233 5.98233 ZT20-23 1.918595 1.918595 1.918595