Data Collectionmedium
0:00.0

In a survey with a non-response rate, the population mean Yˉ\bar{Y} can be decomposed as Yˉ=WrYˉr+WnrYˉnr\bar{Y} = W_r\bar{Y}_r + W_{nr}\bar{Y}_{nr}, where rr denotes respondents and nrnr non-respondents. If a researcher assumes Yˉnr=Yˉr\bar{Y}_{nr} = \bar{Y}_r, what is the bias in the estimate?