Chapter 8: Estimation

A point estimator is just the statistic that you have calculated previously. As an example, when you wanted to estimate the population mean, $\mu$, the point estimator is the sample mean, $\bar{x}$. To estimate the population proportion, p, you use the sample proportion, $\widehat{p}$. In general, if you want to estimate any population parameter, we will call it $\theta$, you use the sample statistic, $\widehat{\theta }$.

Point estimators are really easy to find, but they have some drawbacks. First, if you have a large sample size, then the estimate is better. But with a point estimator, you don’t know what the sample size is. Also, you don’t know how accurate the estimate is. Both of these problems are solved with a confidence interval.