condition mean min max ZT0-3 6.111106666666666 5.66585 6.73681 ZT4-7 6.0209150000000005 6.0209150000000005 6.0209150000000005 ZT8-11 5.793699999999999 5.793699999999999 5.793699999999999 ZT12-15 6.822190000000001 5.79544 7.848940000000001 ZT16-19 7.064085 7.064085 7.064085 ZT20-23 8.745585 8.745585 8.745585