anchor.diff:  deviation.
   
   Let's see what calling the `describe()` method on the Fare columns gives us when
  -we run it, as shown in listing 2.7:
  +we run it, as shown in listing 2.8.
   
   .Calling the describe method on the Fare column gives us summary statistics.
  +[source,scala]
   ----
   titanicTrain
     .describe("Fare") // <1>
  
positive.code: |===
  
  If we were to apply a VectorAssembler with Age and Fare as input columns, we
  would obtain table 2.9.
  
  .Resulting DataFrame after applying a VectorAssembler on the Age and Fare columns.
  [options="header"]
  
negative.code: It adds a column to an existing DataFrame containing a vector, being the
  concatenation of the values from the specified columns.
  
  As an example, let's consider the synthetic DataFrame in table 2.10.
  
  .DataFrame containing an Age and a Fare column.
  [options="header"]
  