condition mean min max ZT0-3 9.7604425 8.88027 10.640615 ZT4-7 11.7641 11.7641 11.7641 ZT8-11 10.734549999999999 10.734549999999999 10.734549999999999 ZT12-15 0 0 0 ZT16-19 10.64275 10.64275 10.64275 ZT20-23 13.701699999999999 13.701699999999999 13.701699999999999