Monday, September 21, 2015

Correlation example using research study about reusable shopping bags/shopping habits

A few weeks ago, I used an NPR story in order to create an ANOVA example for use in class. This week, I'm giving the same treatment to a different research study discussed on NPR and turning it into a correlation example.

A recent research study found that individuals who use reusable grocery store bags tend to spend more on both organic food AND junk food.

Here is NPR's treatment of the researchHere is a more detailed account of the research via an interview with one of the study's authors. Here is the working paper that the PIs have released for even more detail. 

The researchers frame their findings (folks who are "good" by using resuable bags and purchasing organic food then feel entitled to indulge in some chips and cookies) via "licensing", but I think this could also be explained by ego depletion (opening up a discussion about that topic).

So, I created a little faux data set that replicates the main finding: Folks who use reusable bags have high rates of both organic and junk food purchasing. I decided to replicate the findings as a very simple correlation. This data set represents one year's worth of grocery store spending on Junk Food and Organic Food among reusable bag users.  I created this data set using Richard Landers' data generator website.

$ on Junk Food$ on Organic Food

This radio story let's you discuss cutting edge consumer psychology research. It let's you break up your classroom time with an NPR radio story. It provides another example for data analysis in which your students know the end result, which I think is appropriate for an introductory correlation lecture. Additionally, this story is an example of wide spread data collection/data mining, as the data in question (real data, not my faux data) came from consumer loyalty grocery store cards.