What type of geom should you use to create a scatterplot in ggplot2?

point_geom scatter_geom xy_geom density_geom

Which package do you need to run the function 'fread'?

data.table ggplot2 tidyr foreign

Decision tree classifiers are what?

Simple and transparent complex and opaque Complex but transparent Simple but opaque

What can you do with the 'by' parameter of a data.table?

Group the output table Select a specific column Add an extra row to your dataset Connect several filter criteria

What function do you use in the caret package to determine the accuracy of your machine learning models?

confusionMatrix() predict() score() accuracy()