condition mean min max ZT0-3 11.06705 11.06705 11.06705 ZT4-7 8.991865 8.991865 8.991865 ZT8-11 6.9757750000000005 6.9757750000000005 6.9757750000000005 ZT12-15 9.419705 9.419705 9.419705 ZT16-19 8.97385 8.97385 8.97385 ZT20-23 10.8594 10.8594 10.8594