condition mean min max ZT0-3 2.074645 2.074645 2.074645 ZT4-7 1.116435 1.116435 1.116435 ZT8-11 1.425145 1.425145 1.425145 ZT12-15 1.55359 1.55359 1.55359 ZT16-19 2.279035 2.279035 2.279035 ZT20-23 1.8029950000000001 1.8029950000000001 1.8029950000000001