condition mean min max ZT0-3 7.821965 7.821965 7.821965 ZT4-7 8.277017 8.277017 8.277017 ZT8-11 8.408082 8.408082 8.408082 ZT12-15 8.132554500000001 8.132554500000001 8.132554500000001 ZT16-19 8.863559 8.863559 8.863559 ZT20-23 9.20234 9.20234 9.20234