condition mean min max ZT0-3 3.437876666666667 2.31751 4.45831 ZT4-7 3.222085 3.222085 3.222085 ZT8-11 3.15592 3.15592 3.15592 ZT12-15 3.8359 3.0164 4.6554 ZT16-19 3.340055 3.340055 3.340055 ZT20-23 3.9656700000000003 3.9656700000000003 3.9656700000000003