condition mean min max ZT0-3 7.514383 7.514383 7.514383 ZT4-7 7.3210905 7.3210905 7.3210905 ZT8-11 6.72991 6.72991 6.72991 ZT12-15 7.545665 7.545665 7.545665 ZT16-19 7.815676 7.815676 7.815676 ZT20-23 8.0699595 8.0699595 8.0699595