cm011 2015-10-13 Tuesday overview

• HW04 will be due ?? sometime Friday 2015-10-16 ??. Write a function, documenting process from interactive pilot to formal tests. Apply function to Gapminder using dplyr or, maybe, plyr. Invitation to experiment with broom and then do more split-apply-combine or visualization on the results.
• Writing your own functions. You should have finished this on your own.
  • Write your own R functions, part 1
  • Write your own R functions, part 2
  • Write your own R functions, part 3
• Data aggregation
  • Big picture slides linked and embedded below
  • Guided challenge: write function to regress life expectancy on year and return the estimated intercept and slope
  • Use dplyr::do() to apply this function to each country in Gapminder; use broom to do same in a slick way to linear models in general
  • Use plyr::ddply() to apply this function to each country in Gapminder 2014 material I’m keeping around and linked, just in case
• What’s left for 545?
  • Tidy data and reshaping
  • Be the boss of your factors
  • Back to figs: practical matters (e.g. color and file management), guest lecture from Tamara Munzner