Chi Squared, regression and causation
Tuesday 14 April 2015
Both tests on the same data?
This is a quick blog post about a couple of discussions I have had recently about students using both Linear regression and independence tests with the same data! I wrote this in a correspondence recently and thought it worth sharing. Comments welcomed!
HOWEVER - this does not mean students cant use both.... eg a project might be investigating literacy rates and involve a scatter graph of literacy against GDP, and then a chi² to see if literacy rate is dependent on continent for example. This is great. In this case the student has used both tests to investigate a theme involving literacy rates but not on exactly the same data.
I summary, my advice is that students avoid doing both tests on the same data, but there is no official line that it cant be done. If you want to give students full marks then I would advise noting to the moderator where you see the difference. Otherwise I think the relevance can be questioned.'
......... to be continued