condition mean min max ZT0-3 8.521232 8.521232 8.521232 ZT4-7 10.583661 10.583661 10.583661 ZT8-11 10.247432 10.247432 10.247432 ZT12-15 11.81931 11.81931 11.81931 ZT16-19 11.405084 11.405084 11.405084 ZT20-23 9.780849 9.780849 9.780849