condition mean min max ZT0-3 4.155296719 3.310884628 4.99970881 ZT4-7 4.43469419125 4.273454892 4.5959334905 ZT8-11 3.17140051325 2.5414437805 3.8013572460000002 ZT12-15 7.96536027275 5.4375060065 10.493214539 ZT16-19 12.83073473 11.619532669999998 14.041936790000001 ZT20-23 17.4292724925 15.56719023 19.291354755