condition mean min max ZT0-3 5.290386666666667 3.16085 7.75328 ZT4-7 2.6783900000000003 2.6783900000000003 2.6783900000000003 ZT8-11 3.26423 3.26423 3.26423 ZT12-15 5.5823475 5.15601 6.008685 ZT16-19 5.3035499999999995 5.3035499999999995 5.3035499999999995 ZT20-23 6.8193850000000005 6.8193850000000005 6.8193850000000005