condition mean min max ZT0-3 8.065131666666666 6.160495 9.114605000000001 ZT4-7 6.557625 6.557625 6.557625 ZT8-11 5.14781 5.14781 5.14781 ZT12-15 6.96715 6.57141 7.36289 ZT16-19 6.80363 6.80363 6.80363 ZT20-23 8.825420000000001 8.825420000000001 8.825420000000001