condition mean min max ZT0-3 7.203401 7.203401 7.203401 ZT4-7 7.9662805 7.9662805 7.9662805 ZT8-11 8.0795465 8.0795465 8.0795465 ZT12-15 8.3182705 8.3182705 8.3182705 ZT16-19 7.749562 7.749562 7.749562 ZT20-23 11.246860999999999 11.246860999999999 11.246860999999999