condition mean min max ZT0-3 1.9216866666666665 1.707215 2.174775 ZT4-7 1.68064 1.68064 1.68064 ZT8-11 2.20369 2.20369 2.20369 ZT12-15 6.5209875 1.7918500000000002 11.250125 ZT16-19 3.991855 3.991855 3.991855 ZT20-23 1.925825 1.925825 1.925825