condition mean min max ZT0-3 8.68624 8.68624 8.68624 ZT4-7 7.111665 7.111665 7.111665 ZT8-11 7.657795 7.657795 7.657795 ZT12-15 20.50285 20.50285 20.50285 ZT16-19 17.8157 17.8157 17.8157 ZT20-23 12.14485 12.14485 12.14485