condition mean min max ZT0-3 7.8302 7.8302 7.8302 ZT4-7 8.19388 8.19388 8.19388 ZT8-11 7.7613725 7.7613725 7.7613725 ZT12-15 8.458177000000001 8.458177000000001 8.458177000000001 ZT16-19 8.090128 8.090128 8.090128 ZT20-23 7.939599 7.939599 7.939599