condition mean min max ZT0-3 1.7551853333333334 1.217901 2.103205 ZT4-7 2.260225 2.260225 2.260225 ZT8-11 1.8287 1.8287 1.8287 ZT12-15 1.4780912499999999 1.3191825 1.637 ZT16-19 1.241261 1.241261 1.241261 ZT20-23 1.814025 1.814025 1.814025