condition mean min max ZT0-3 7.663989 7.663989 7.663989 ZT4-7 10.0333075 10.0333075 10.0333075 ZT8-11 10.9010905 10.9010905 10.9010905 ZT12-15 8.202202 8.202202 8.202202 ZT16-19 8.623331499999999 8.623331499999999 8.623331499999999 ZT20-23 9.211895 9.211895 9.211895