比较下列两组测定结果的精密度( )甲组:0.19%,0.19%,0.20%,0.21%0.21%。乙组:0.18%,0.20%,0.20%,0.21%,0.22%
A.甲、乙两组相同
B.甲组比乙组高
C.乙组比甲组高
D.无法判断
正确答案是B