condition mean min max ZT0-3 2.4964483333333334 2.046505 3.373275 ZT4-7 0.66514 0.66514 0.66514 ZT8-11 2.023005 2.023005 2.023005 ZT12-15 0.3287325 0.0 0.657465 ZT16-19 2.564285 2.564285 2.564285 ZT20-23 2.156395 2.156395 2.156395