exercise1():
  Get a datafile in text format from the class website.
  Read the data from the datafile.
  Print the first five lines.
  Compute some statistical measurements.
  Normalize the data, and recompute the statistics.
  When finished, delete the datafile.

  "hw_data.txt" contains 25000 rows and 3 columns.

  First five lines of data:

[[ 65.78331 112.9925 ]
 [ 71.51521 136.4873 ]
 [ 69.39874 153.0269 ]
 [ 68.2166  142.3354 ]
 [ 67.78781 144.2971 ]]

  Statistics for data:

    data.shape:      (350, 2)
    np.min(data,axis=0):   [63.19158 84.3598 ]
    np.mean(data,axis=0):  [ 67.95149226 126.84849654]
    np.max(data,axis=0):   [ 73.90107 158.9562 ]
    np.std(data,axis=0):   [ 1.89826152 12.04161047]
    np.var(data,axis=0):   [  3.60339679 145.00038262]
  Graphics saved as "exercise1.png"

exercise1():
  Normal end of execution.