condition mean min max ZT0-3 8.91737 8.91737 8.91737 ZT4-7 9.4066495 9.4066495 9.4066495 ZT8-11 7.888189000000001 7.888189000000001 7.888189000000001 ZT12-15 8.6195515 8.6195515 8.6195515 ZT16-19 8.693375 8.693375 8.693375 ZT20-23 9.082049 9.082049 9.082049