condition mean min max ZT0-3 8.521232 8.521232 8.521232 ZT4-7 11.510318999999999 11.510318999999999 11.510318999999999 ZT8-11 10.9178185 10.9178185 10.9178185 ZT12-15 10.477438 10.477438 10.477438 ZT16-19 10.6542535 10.6542535 10.6542535 ZT20-23 10.154679999999999 10.154679999999999 10.154679999999999