condition mean min max ZT0-3 8.476055 7.248255 9.703855 ZT4-7 8.172600000000001 8.172600000000001 8.172600000000001 ZT8-11 17.7635 17.7635 17.7635 ZT12-15 0 0 0 ZT16-19 18.2691 18.2691 18.2691 ZT20-23 12.259 12.259 12.259