condition mean min max ZT0-3 8.424957500000001 7.52763 9.322285 ZT4-7 9.81443 9.81443 9.81443 ZT8-11 11.142225 11.142225 11.142225 ZT12-15 0 0 0 ZT16-19 9.102170000000001 9.102170000000001 9.102170000000001 ZT20-23 10.53913 10.53913 10.53913