condition mean min max ZT0-3 4.604666666666667 4.170845 5.175485 ZT4-7 4.227914999999999 4.227914999999999 4.227914999999999 ZT8-11 4.075145 4.075145 4.075145 ZT12-15 5.7431149999999995 5.104705 6.381525 ZT16-19 4.000185 4.000185 4.000185 ZT20-23 4.789435 4.789435 4.789435