condition mean min max ZT0-3 12.961898333333332 8.454145 16.6363 ZT4-7 6.940205000000001 6.940205000000001 6.940205000000001 ZT8-11 17.705199999999998 17.705199999999998 17.705199999999998 ZT12-15 19.62405 16.8992 22.3489 ZT16-19 15.456949999999999 15.456949999999999 15.456949999999999 ZT20-23 18.62295 18.62295 18.62295