condition mean min max ZT0-3 308.918841 308.918841 308.918841 ZT4-7 281.3565 281.3565 281.3565 ZT8-11 330.53429 330.53429 330.53429 ZT12-15 381.566005 381.566005 381.566005 ZT16-19 472.4902415 472.4902415 472.4902415 ZT20-23 498.8635125 498.8635125 498.8635125