Exploratory Factor Analysis with SAS

Application

Sample Size and the Precision of Alpha

As we mentioned before, alpha is sample dependent. Thus it might be expected that sample size can affect the precision of our alpha estimate. When a smaller sample is used to estimate alpha, each observation contributes a lot of information to the estimate. An outlier or deviation from expectation in a small sample can have a profound effect on the results and can cause them to vary from the population mean. However, in a larger sample, the outlier or deviation will likely be averaged out by the other observations.

Let’s explore this issue of sample size and precision with the Marsh SDQ data that we’ve been using throughout the book. Let us start by examining the reliability of the parent subscale ...