condition mean min max ZT0-3 2.39003 2.39003 2.39003 ZT4-7 3.529275 3.529275 3.529275 ZT8-11 3.142945 3.142945 3.142945 ZT12-15 2.2816549999999998 2.2816549999999998 2.2816549999999998 ZT16-19 1.97554 1.97554 1.97554 ZT20-23 1.91656 1.91656 1.91656