condition mean min max ZT0-3 8.216295 8.216295 8.216295 ZT4-7 9.1743055 9.1743055 9.1743055 ZT8-11 8.075688 8.075688 8.075688 ZT12-15 9.058164999999999 9.058164999999999 9.058164999999999 ZT16-19 8.999156 8.999156 8.999156 ZT20-23 9.61925 9.61925 9.61925