Introduction When reporting on data, we usually summarize our variables. The most basic way for doing so is presenting their frequency distributions. Visualizing these as histograms tends to give immediate insight into what a variable ‘looks like’, especially when many distinct values are present. However, frequency distributions often provide more detail than we actually need. […]
Introduction A previous tutorial introduced some summary statistics appropriate for both categorical as well as metric variables. Now it’s time to turn to some measures that apply to metric variables exclusively. The most important ones are the mean (or average), variance and standard deviation. Mean Most of us are probably familiar with the mean (or average) but […]
Summary SPSS DESCRIPTIVES generates a single table with descriptive statistics for one or more variables. It can also add z-scores to your data. We’ll walk through its major options using freelancers.sav. The screenshot below shows part of its data view. User Missing Values Before running any descriptives, we first need to specify some user missing values for income_2010 through […]
This tutorial shows how to compute means over both variables and cases in a simple but solid way. We encourage you follow along by downloading and opening restaurant.sav, part of which is shown below. Quick Data Check Before computing anything whatsoever, we always need to know what’s in our data in the first place. Skipping this […]
A course was evaluated by 183 students. The data are in course_evaluation.sav, part of which is shown below. The teacher wants to know the average age of his students but we only have their date of birth. 1. Ensure Date of Birth is a Date Variable The first thing we’ll do is check if date of […]
