condition mean min max ZT0-3 27.857875 26.3524 29.36335 ZT4-7 17.29855 17.29855 17.29855 ZT8-11 14.5824 14.5824 14.5824 ZT12-15 0 0 0 ZT16-19 26.8348 26.8348 26.8348 ZT20-23 30.0447 30.0447 30.0447