condition mean min max ZT0-3 7.324444444333333 7.324444444333333 7.324444444333333 ZT4-7 6.997222222 6.997222222 6.997222222 ZT8-11 7.128888889000001 7.128888889000001 7.128888889000001 ZT12-15 5.431111111 5.431111111 5.431111111 ZT16-19 4.621111111333334 4.621111111333334 4.621111111333334 ZT20-23 5.307777778 5.307777778 5.307777778