condition mean min max ZT0-3 7.8881274999999995 7.38022 8.396035 ZT4-7 8.35473 8.35473 8.35473 ZT8-11 6.0886700000000005 6.0886700000000005 6.0886700000000005 ZT12-15 0 0 0 ZT16-19 7.997254999999999 7.997254999999999 7.997254999999999 ZT20-23 7.823964999999999 7.823964999999999 7.823964999999999