R ships with several built-in datasets, including the famous iris¹ (flowers, not eyes) data collected by Anderson and analyzed by Fisher in the 1930s. You can look at the help page of iris to see the structure of this dataset. Create a new data frame iris_num that consists of the numeric columns of the iris dataset. Calculate the means of these columns and store them in a vector iris_avg.

(from: Cotton, 2013, Learning R, O’Reilly)