A quality describing a sample designed in such a way that audience projections may be made.
A quality describing a sample designed in such a way that audience projections may be made.
表示的是一种样本质量.即可使用该样本来预测全体人口.
A quality describing a sample designed in such a way that audience projections may be made.
表示的是一种样本质量.即可使用该样本来预测全体人口.