condition mean min max ZT0-3 6.052041666666667 5.03118 6.633295 ZT4-7 5.218064999999999 5.218064999999999 5.218064999999999 ZT8-11 5.417479999999999 5.417479999999999 5.417479999999999 ZT12-15 5.9574625 5.4885649999999995 6.42636 ZT16-19 6.683095 6.683095 6.683095 ZT20-23 6.637095 6.637095 6.637095