condition mean min max ZT0-3 19.610625 19.15215 20.0691 ZT4-7 17.9628 17.9628 17.9628 ZT8-11 17.88645 17.88645 17.88645 ZT12-15 0 0 0 ZT16-19 18.27655 18.27655 18.27655 ZT20-23 19.546 19.546 19.546