condition mean min max ZT0-3 6.1062475 5.4963049999999996 6.71619 ZT4-7 6.139995 6.139995 6.139995 ZT8-11 7.536289999999999 7.536289999999999 7.536289999999999 ZT12-15 0 0 0 ZT16-19 10.394919999999999 10.394919999999999 10.394919999999999 ZT20-23 10.045304999999999 10.045304999999999 10.045304999999999