condition mean min max ZT0-3 5.379156666666667 4.643435 5.818045 ZT4-7 3.9853050000000003 3.9853050000000003 3.9853050000000003 ZT8-11 4.197005 4.197005 4.197005 ZT12-15 6.119535 5.75622 6.48285 ZT16-19 6.062605 6.062605 6.062605 ZT20-23 6.618755 6.618755 6.618755