An overview of statistial learning
Statistical learning refers to a vast set of tools for understanding data.
Two categories: supervised and unsupervised.
Supervised: Build models based on known input and output data, then use the model
for prediction or estimation.
Unsupervised: There are inputs but no supervised outputs. We can learn
relationships and structures from such data.
Notation and simple algebra
The $ X_{ij} $ represents the value for the $ jth $ variable for the $ ith $ observation, where $ i=1,2,…n $ and $ j=1,2,…n $.
get the R package
install.packages("ISLR")