Tutorial 7: Chi-squared

Exploring data
  • nrow() - number of participants
  • ncol()- number of columns
  • names() - get variable names
Visualising counts with bar charts

  • geom_bar() - creates a bar chart

    • basic example

    • detailed example

Chi-Square analysis
  • chisq.test() - performs an χ2 test of association
    • example
Observed and expected frequencies
  • str() - used to look at the structure of object (with the results of a test stored in it???)
    • example
  • expected frequencies should be above 5 (not sure why?)