condition mean min max ZT0-3 10.349395 10.349395 10.349395 ZT4-7 8.8898075 8.8898075 8.8898075 ZT8-11 9.56479 9.56479 9.56479 ZT12-15 8.9509475 8.9509475 8.9509475 ZT16-19 9.0965325 9.0965325 9.0965325 ZT20-23 9.394845 9.394845 9.394845