PO218 Lecture Notes - Lecture 6: Confidence Interval, Interval Estimation, Error Bar
Document Summary
It is also called the margin of sampling error, or just sampling error. Bias and efficiency: bias: a criterion used to select sample statistics for estimation procedures. A statistic is unbiased if the mean of its sampling distribution is equal to the population value of interest: efficiency: the extent to which sample outcomes are clustered around the mean of the sampling distribution. The smaller the standard deviation of a sampling distribution, the greater the clustering and the higher of the efficiency. That is, if we calculate sample proportions from repeated random samples of size n and then array them in a frequency polygon, the sample distribution of sample proportions will have a mean ( p) equal to the population proportion (pu). Knowing that sample means and proportions are unbiased allows us to determine the probability that they lie within a given distance of the population value we are trying to estimate.
