condition mean min max ZT0-3 5.494095 5.494095 5.494095 ZT4-7 2.574945 2.574945 2.574945 ZT8-11 6.645945 6.645945 6.645945 ZT12-15 7.86768 7.86768 7.86768 ZT16-19 11.534849999999999 11.534849999999999 11.534849999999999 ZT20-23 7.62477 7.62477 7.62477