condition mean min max ZT0-3 4.111775 3.787425 4.4361250000000005 ZT4-7 4.334925 4.334925 4.334925 ZT8-11 5.282445 5.282445 5.282445 ZT12-15 0 0 0 ZT16-19 7.880635 7.880635 7.880635 ZT20-23 7.0493950000000005 7.0493950000000005 7.0493950000000005