condition mean min max ZT0-3 7.673531 7.673531 7.673531 ZT4-7 8.1491745 8.1491745 8.1491745 ZT8-11 7.9723755 7.9723755 7.9723755 ZT12-15 7.9397135 7.9397135 7.9397135 ZT16-19 7.1903135 7.1903135 7.1903135 ZT20-23 7.7509035 7.7509035 7.7509035