condition mean min max ZT0-3 1.484635 1.484635 1.484635 ZT4-7 0.693832 0.693832 0.693832 ZT8-11 1.556025 1.556025 1.556025 ZT12-15 1.771285 1.771285 1.771285 ZT16-19 2.50772 2.50772 2.50772 ZT20-23 1.278675 1.278675 1.278675