Code for RSTUDIO

rm(list=ls()) #Clear memory

#install.packages('quantmood')

library('quantmod')

stocks=c('KO','PEP','^SPX')

getSymbols(stocks,src='yahoo', from="2022-12-30", to="2023-12-31", periodicity = 'daily') #  since 2022/Dec/30

KO_Prices<-KO$KO.Adjusted

PEP_Prices<-PEP$PEP.Adjusted

SP500_Prices<-SPX$SPX.Adjusted

PEP_R<-diff(PEP_Prices)/lag(PEP_Prices)

KO_R<-diff(KO_Prices)/lag(PEP_Prices)

SPX_R<-diff(SP500_Prices)/lag(SP500_Prices)

lm(PEP_R~SPX_R) # beta for PEP

summary(PEP_R,na.rm = 'true')

var(PEP_R,na.rm = 'true') # variance for PEP (non-annualized)

var(PEP_R,na.rm = 'true')

var(PEP_R,KO_R,na.rm = 'true'