condition mean min max ZT0-3 10.679207 10.679207 10.679207 ZT4-7 14.209685 14.209685 14.209685 ZT8-11 15.501446000000001 15.501446000000001 15.501446000000001 ZT12-15 13.0186675 13.0186675 13.0186675 ZT16-19 12.967483999999999 12.967483999999999 12.967483999999999 ZT20-23 11.9708835 11.9708835 11.9708835