The ozone data frame has 552 rows and 3 columns. The first column is the mean monthly ozone concentration in Dobson units of the ozone layer at Arosa, Switzerland, from 1926 to 1971.
A data frame with 518 observations on the following 3 variables.
: mean monthly ozone in Dobson units
: year in which measurements were taken (4 digits)
: month in which measurements were taken (3 letter abbreviation)