condition mean min max ZT0-3 246.443771 246.443771 246.443771 ZT4-7 271.959073 271.959073 271.959073 ZT8-11 252.842888 252.842888 252.842888 ZT12-15 289.8422005 289.8422005 289.8422005 ZT16-19 276.7553335 276.7553335 276.7553335 ZT20-23 348.82482300000004 348.82482300000004 348.82482300000004