anchor.diff:  }
   ----
   
  -We can perform `statistical analysis` on arrays.
  +We can perform *statistical analysis* on arrays.
   
   For example we can correlate two sequences with the `corr` function:
   
  
positive.code: 
  === Vectors
  
  But how to create the vectors from a our data set. Remember we have un-aggregated room rates from each of the cities.
  How can we vectorize the data so it can be compared using the `distance` function.
  
  We have a Streaming Expression that can take a *random sample* from each of the cities. The name of this
  expression is `random`. So we could take a random sample of 1000 room rates from each of the five markets.
  
  But random vectors of room rates are not comparable because the distance algorithm compares values at each index
  in the vector. How can make these vectors comparable?
  
  We can make them comparable by *sorting* them. Then as the distance algorithm moves along the vectors it will be
  comparing room rates from lowest to highest in both markets.
  
  === The code
  
  
negative.code: 
  We can manipulate arrays with functions.
  
  For example we can reverse and array with the `rev` function:
  
  [source,text]
  ----
  