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.
  Already have a copy of hw_data.txt

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

  First five lines of data:

  (0)          66   1.1e+02
  (1)          72   1.4e+02
  (2)          69   1.5e+02
  (3)          68   1.4e+02
  (4)          68   1.4e+02

  Statistics for data:

  Minimum           63        84
  Maximum           74   1.6e+02
  Range             11        75
  Mean              68   1.3e+02
  Variance         3.6   1.5e+02
  STD              1.9        12
  RMS            9e+02   1.7e+03
  Graphics saved as "exercise1.jpg"

  Covariance matrix for data2:

[[1.00286533 0.48891797]
 [0.48891797 1.00286533]]

  Covariance matrix for data2:

[[1.00286533 0.48891797]
 [0.48891797 1.00286533]]

  Deleting dataset file:

exercise1():
  Normal end of execution.