condition mean min max ZT0-3 8.504444444333332 8.504444444333332 8.504444444333332 ZT4-7 6.64 6.64 6.64 ZT8-11 8.127222222333334 8.127222222333334 8.127222222333334 ZT12-15 8.390000001 8.390000001 8.390000001 ZT16-19 8.022222222 8.022222222 8.022222222 ZT20-23 9.371111110000001 9.371111110000001 9.371111110000001