condition mean min max ZT0-3 5.26019 4.987115 5.505075 ZT4-7 3.940535 3.940535 3.940535 ZT8-11 4.93348 4.93348 4.93348 ZT12-15 8.70374 8.374435 9.033045 ZT16-19 8.158159999999999 8.158159999999999 8.158159999999999 ZT20-23 8.052245 8.052245 8.052245