condition mean min max ZT0-3 8.526645 8.526645 8.526645 ZT4-7 7.919045 7.919045 7.919045 ZT8-11 7.197430000000001 7.197430000000001 7.197430000000001 ZT12-15 8.091195 8.091195 8.091195 ZT16-19 10.6674 10.6674 10.6674 ZT20-23 9.32965 9.32965 9.32965