condition mean min max ZT0-3 18.719228 18.719228 18.719228 ZT4-7 16.6857855 16.6857855 16.6857855 ZT8-11 14.351583999999999 14.351583999999999 14.351583999999999 ZT12-15 14.372002 14.372002 14.372002 ZT16-19 14.674254000000001 14.674254000000001 14.674254000000001 ZT20-23 15.407782 15.407782 15.407782