condition mean min max ZT0-3 12.178155 5.510615 16.65285 ZT4-7 3.311395 3.311395 3.311395 ZT8-11 4.523865000000001 4.523865000000001 4.523865000000001 ZT12-15 7.6792375 6.33145 9.027025 ZT16-19 12.85065 12.85065 12.85065 ZT20-23 21.5426 21.5426 21.5426