4. Which statistical test to use?

You need a p-value, and badly. How do you figure out which test to use?

> cheat sheet file for you to print: 'which test do i use' - will give you a fast summary of typical choices for which stats test to use. There are most definitely more sophisticated decision trees, but this will get you started.

> Read a whole (free) text book: Openstax Intro to Statistics

> Complete a whole (free) Online courses:

Penn State has a great online Stats program:

1. Elementary Statistics: distributions, hypothesis testing, ANOVA
2. Design of Experiments: simple comparative experiments, factorial designs, blocking, linear regression...
3. Topics in R statistical Language: a bigger, bolder version of the ABC site. Definitely download/read/use the pdf "EssentialR"

Psych folks like Likert scales:

Likert scales can be tested with parametric tests: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3886444/

The Personality Project has a complete R package with all the psych test functions evaR! They even have a get staRted page, too.