condition mean min max ZT0-3 12.498455 12.498455 12.498455 ZT4-7 15.35276 15.35276 15.35276 ZT8-11 14.80222 14.80222 14.80222 ZT12-15 14.677285 14.677285 14.677285 ZT16-19 15.9123 15.9123 15.9123 ZT20-23 13.52658 13.52658 13.52658