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QUAN 2010 Notes Introduction to Business Statistics

Section 9.1 Point Estimates

Definition 9.1.1.

A point estimate is a single numerical value that best estimates the population parameter of interest.
The most common point estimates are the sample mean, \(\overline{x}\text{,}\) and the sample proportion, \(\overline{p}\text{.}\)
The advantage of a point estimate is that it is easy to calculate and easy to understand. The disadvantage is that it doesnโ€™t provide any information about the accuracy of the estimate. For this reason, statisticians prefer an interval estimate, a range of values used to estimate the parameter. This estimate may or may not contain the value of the parameter being estimated.
For example, letโ€™s say we work for a company with 500 employees, and we want to understand what proportion of employees is happy with their health benefits. We sample 20 employees, and in that sample, \(65\%\) of the employees are happy with their health benefits. It is probably not the case that exactly \(65\%\) of all employees are happy with their health benefits. However, we would like to use that point estimate of \(65\%\) to estimate the true proportion of all employees that is happy with their health benefits.