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 (shuffling the response variable).
  • 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 in the population and to estimate the population slope.

Download the word file for saving your output: Lab8report.doc.

When you are ready, click Start to begin.

Start Lab