Assignment 4

## tibble [54 × 2] (S3: tbl_df/tbl/data.frame)
##  $ Income           : num [1:54] 20 22 24 26 27 30 31 32 33 34 ...
##  $ Average Frequency: num [1:54] 2 3 1 3 4 ...

## tibble [552 × 2] (S3: tbl_df/tbl/data.frame)
##  $ Month : POSIXct[1:552], format: "1947-02-01" "1947-03-01" ...
##  $ Return: num [1:552] 0.0309 -0.0269 -0.0305 -0.0152 0.0302 ...