condition mean min max ZT0-3 27.321276 27.321276 27.321276 ZT4-7 23.040205 23.040205 23.040205 ZT8-11 27.138438999999998 27.138438999999998 27.138438999999998 ZT12-15 31.099973000000002 31.099973000000002 31.099973000000002 ZT16-19 30.962386000000002 30.962386000000002 30.962386000000002 ZT20-23 31.4398185 31.4398185 31.4398185