R Markdown and Data structures: Quantitative stats lab

$7.$ Built$-$In Data Frames

a$.$ Load the built$-$in data frame airquality and display the first six rows of data.

b$.$ Isolate the variable, Ozone. What type of variable is this?

c$.$ Using the proper type of graph, display the data for the Ozone variable. Make

sure to add a title, axes labels, and choose a color.

d$.$ Using the airquality data frame as an example, explain what an index variable is$.$

How does this impact the validity of your measurement?