condition mean min max ZT0-3 8.400805 8.400805 8.400805 ZT4-7 6.18189 6.18189 6.18189 ZT8-11 7.01512 7.01512 7.01512 ZT12-15 6.836040000000001 6.836040000000001 6.836040000000001 ZT16-19 9.535985 9.535985 9.535985 ZT20-23 8.921035 8.921035 8.921035