Oct. 8, 2008— -- Surveys based on a random sample of respondents are subject to sampling error – a calculation of how closely the results reflect the attitudes ...

Yet, when polling is based on a probability sample, we can calculate the amount of imprecision in our estimates. That calculation is based on two things: the size of the sample and the population from ...

In presidential elections, even the smallest changes in horse-race poll results seem to become imbued with deep meaning. But they are often overstated. Pollsters ...

Describe the abstract idea of a sampling distribution and how it reflects the sample to sample variability of a sample statistic or point estimate. Identify the ...

A behind-the-scenes blog about research methods at Pew Research Center. For our latest findings, visit pewresearch.org. Every survey finding published by Pew Research ...

We have previously discussed the importance of estimating uncertainty in our measurements and incorporating it into data analysis 1. To know the extent to which we can generalize our observations, we ...