condition mean min max ZT0-3 8.801912 8.801912 8.801912 ZT4-7 7.634092000000001 7.634092000000001 7.634092000000001 ZT8-11 8.216624 8.216624 8.216624 ZT12-15 9.917447500000002 9.917447500000002 9.917447500000002 ZT16-19 8.3479875 8.3479875 8.3479875 ZT20-23 10.4505215 10.4505215 10.4505215