ozone.NY data frame consists of hourly O_3
concentration levels (ppb) from nine stations in New York State
numbered for our purposes from 1 to 9. These data were originally
downloaded from the EPA's AIRS air quality site (Environmental
Protection Agency 2013). Furthermore, preliminay analysis
suggested a sqrt transformation of the original concentrations to
symmetrize the data distribution.
Each row of the data set represents a daily record starting at April 1, 1995, and ending at September 30, 1995 (183 days). Measurements are recorded by station in columns, with four columns per station (for hours 8–12); there are nine stations, so there are 36 columns of measurements in total.
The last six stations have no missing observations while stations 1, 2, 3 have 2616, 2016, and 72 missing hourly observations, respectively.
month of the measurement, numeric 4–9
day of the week, numeric 2–8
square root of the O_3 measurement for station 1 for hours 8–12 (8am to noon).
square root of the O_3 measurement for station 9 for hours 8–12 (8am to noon).
US Environmental Protection Agency's AIRS air quality site (2013), http://www.epa.gov/ttn/airs/airsaqs/.