condition mean min max ZT0-3 1.8233375 1.6980499999999998 1.948625 ZT4-7 1.90289 1.90289 1.90289 ZT8-11 1.840255 1.840255 1.840255 ZT12-15 0 0 0 ZT16-19 1.720935 1.720935 1.720935 ZT20-23 1.654195 1.654195 1.654195