condition mean min max ZT0-3 50.767187 50.767187 50.767187 ZT4-7 34.5302935 34.5302935 34.5302935 ZT8-11 28.334971499999998 28.334971499999998 28.334971499999998 ZT12-15 25.450827500000003 25.450827500000003 25.450827500000003 ZT16-19 22.311622 22.311622 22.311622 ZT20-23 16.3163725 16.3163725 16.3163725