condition mean min max ZT0-3 15.663284 15.663284 15.663284 ZT4-7 12.3263055 12.3263055 12.3263055 ZT8-11 9.752932000000001 9.752932000000001 9.752932000000001 ZT12-15 11.996443 11.996443 11.996443 ZT16-19 11.564052 11.564052 11.564052 ZT20-23 11.0072875 11.0072875 11.0072875