condition mean min max ZT0-3 3.15240521 2.4462656309999997 3.858544789 ZT4-7 4.0188538795 3.5047406265 4.5329671325 ZT8-11 4.0227050465000005 3.958590891 4.086819202 ZT12-15 7.279338221250001 4.977729866500001 9.580946576 ZT16-19 10.694017709250002 9.2398961985 12.148139220000001 ZT20-23 13.492678560000002 13.15515459 13.830202530000001