Determining Which Method to use Section 8.5

Objectives Determine which method to use when constructing a confidence interval

Determine which method to use when constructing a confidence interval Objective 1 Determine which method to use when constructing a confidence interval

Determine Which Method to Use One of the challenges in constructing a confidence interval is to determine which method to use. The first step is to determine which type of parameter we are estimating. There are three types of parameters for which we have learned to construct confidence intervals: Population mean 𝜇 Population proportion 𝑝 Population standard deviation 𝜎 or variance 𝜎 2

Estimating the Population Mean 𝜇 If you are estimating the population mean 𝝁, there are two methods for constructing a confidence interval: the 𝒛-method and the 𝒕 method. To determine which method to use, we must determine whether the population standard deviation is known, whether the population is approximately normal, and whether the sample size is large (𝑛 > 30). The diagram below can help you with the correct choice.

You Should Know… How to determine which method to use when constructing a confidence interval