condition mean min max ZT0-3 16.859405 16.859405 16.859405 ZT4-7 15.229231 15.229231 15.229231 ZT8-11 14.493248000000001 14.493248000000001 14.493248000000001 ZT12-15 12.943579499999998 12.943579499999998 12.943579499999998 ZT16-19 14.390259 14.390259 14.390259 ZT20-23 14.258009 14.258009 14.258009