Construct a stipchart of the values in `problem.1.data`. Do you see any evidence of any outliers?
Repair this outlier.
    First, report the location of the outlier.
    Next, convert the value to `NA`.
    Finally, display the value of the vector at this location, and show that it has the value `NA`.
Construct a stripchart of the repaired version of `problem.1.data`. Do you see any indication of a -9 being used to represent a missing value?
Directly display all the levels of this factor variable.