The document discusses stock prices and rates of return using Intel Corporation stock as an example. It provides adjusted closing prices for Intel stock from August 2006 to August 2016 sampled monthly. It defines simple and natural log rates of return calculated from the stock prices and discusses how dividends and stock splits are handled. The document also discusses how random errors in stock prices accumulate and how rates of return are distributed, noting that additive errors accumulate normally while multiplicative errors accumulate lognormally. Various R commands for analyzing distributions and rates of return are also provided.