Lab 8: Facebook and Brain Density
Background: How many Facebook friends do you have? Does everyone have the same amount? What might explain some of the variation in the number of friends? Researchers (Kanai, R., Bahrami, B., Roylance, R., and Rees, G., 2011) recently examined the relationship between number of (self-reported) Facebook friends and “grey matter density” in different regions of the brain (links). These regions have previously been linked to social perception and associative memory. The researchers performed MRI scans on students at University College, London. You will examine results for the left middle temporal gyrus (which has been linked in other studies to face recognition) from the follow-up study of 40 student volunteers.
Research Conjecture: Facebook use swells the size of brain regions devoted to tracking and maintaining relationships.
Goals: In this lab you will explore:
- Effective ways of displaying and describing the association between two quantitative variables.
- A numerical measure of the strength of the linear relationship between two quantitative variables.
- A mathematical model (the regression equation) for predicting brain density from number of Facebook friends.
- The sampling variability in regression equations from repeated re-randomizations (scrambles).
- Test of significance and confidence interval procedures for deciding when an observed relationship is statistically significant to help decide whether we have convincing evidence of a genuine association between quantitative variables and to estimate the population slope.
Technology:This lab will use an applet that should work in Firefox, Safari, and Chrome but not Internet Explorer. There is also a Flash demo that requires that you can run Flash on your computer.
Download the word file for saving your output: Lab8report.doc