Please follow the following instructions. The instructions indicate how to download daily stock price of Apple, Inc. from 2016-01-01 to 2018-07-31 from Yahoo! Finance.

library(quantmod)

getSymbols("AAPL", src = "yahoo", from='2016-01-01', to='2018-07-31')

AAPLAdj <- AAPL$AAPL.Adj

(By here the data can be downloaded and extracted using RStudio)

a) Show whether the series AAPLAdj evolves with time. If it does, show how to remove the evolution with time and comment on the result.

b) The following code will convert AAPLAdj to monthly log return.

monthly.AAPL <- monthlyReturn(AAPLAdj, subset=NULL, type='log', leading=TRUE) Find sample autocorrelation and partial autocorrelation estimates for monthly.AAPL up to lag 15.