condition mean min max ZT0-3 3.996428504 3.996428504 3.996428504 ZT4-7 3.5238050000000003 3.5238050000000003 3.5238050000000003 ZT8-11 4.34347 4.34347 4.34347 ZT12-15 5.4107199999999995 5.4107199999999995 5.4107199999999995 ZT16-19 6.182653333333334 6.182653333333334 6.182653333333334 ZT20-23 6.559699999999999 6.559699999999999 6.559699999999999