> library(readr)

> library(lubridate)

Attaching package: 'lubridate'

The following objects are masked from 'package:base':

    date, intersect, setdiff, union


> library(dplyr)

Attaching package: 'dplyr'

The following objects are masked from 'package:stats':

    filter, lag

The following objects are masked from 'package:base':

    intersect, setdiff, setequal, union


> url <- "https://pages.stern.nyu.edu/adesouza/rworkshop/outcsv/returns_of_4_large_stocks.csv"

> 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)) %>% ren .... [TRUNCATED] 

> finaldata <- inner_join(processed_data, return_data, 
+     by = c("ticker", "retdate"))

> finaldata %>% ungroup() %>% group_by(rank) %>% summarize(meanret = mean(ret))
# A tibble: 2 × 2
   rank meanret
  <int>   <dbl>
1     1  0.0234
2     2  0.0226