condition mean min max ZT0-3 9.422181666666667 7.210565 11.27825 ZT4-7 6.803435 6.803435 6.803435 ZT8-11 7.434975 7.434975 7.434975 ZT12-15 9.49708 7.88721 11.106950000000001 ZT16-19 9.22534 9.22534 9.22534 ZT20-23 11.243459999999999 11.243459999999999 11.243459999999999