condition mean min max ZT0-3 2.326843333333333 1.501925 3.22066 ZT4-7 0.861777 0.861777 0.861777 ZT8-11 1.6221299999999998 1.6221299999999998 1.6221299999999998 ZT12-15 1.45864225 1.1812845 1.736 ZT16-19 2.0570245000000003 2.0570245000000003 2.0570245000000003 ZT20-23 3.222305 3.222305 3.222305