condition mean min max ZT0-3 1.0848016666666667 1.043344 1.129891 ZT4-7 1.081955 1.081955 1.081955 ZT8-11 1.1574499999999999 1.1574499999999999 1.1574499999999999 ZT12-15 1.2905099999999998 1.20515 1.37587 ZT16-19 1.212935 1.212935 1.212935 ZT20-23 1.50298 1.50298 1.50298