library(readr)
library(lubridate)

library(dplyr)

# URL of the CSV file
url <- "https://pages.stern.nyu.edu/adesouza/rworkshop/outcsv/returns_of_4_large_stocks.csv"

# Read the CSV file from the internet
data <- read.csv(url)

return_data<-data%>%rename(retdate=date)%>%mutate(retdate=ymd(retdate))

processed_data<-data%>%mutate(date=ymd(date))%>%
  arrange(date, ret)%>%
  group_by(date)%>%
  mutate(rank=ntile(ret,2))%>%
  rename(rankdate=date)%>%
  select(ticker,rankdate, rank)%>%
  mutate(retdate=rankdate+days(1)+months(1)-days(1))

finaldata<-inner_join(processed_data, return_data, by=c("ticker", "retdate"))
finaldata%>%ungroup()%>%
  group_by(rank)%>%
  summarize(meanret=mean(ret))