condition mean min max ZT0-3 213.729978 213.729978 213.729978 ZT4-7 272.9503735 272.9503735 272.9503735 ZT8-11 421.87918049999996 421.87918049999996 421.87918049999996 ZT12-15 497.5438265 497.5438265 497.5438265 ZT16-19 791.2231899999999 791.2231899999999 791.2231899999999 ZT20-23 696.167987 696.167987 696.167987