exercise4():
  Get a datafile in csv format from the class website.
  Read the data from the datafile into a pandas() dataframe.
  Print the first five lines.
  Copy the data from the dataframe into a numpy() array.
  Make a histogram of some of the features.
  Compute some statistical measurements.
  Standardize the data, and recompute the statistics.
  When finished, delete the datafile.
  Downloading dataset file:
       Pregnancies     Glucose   Diastolic  ...    Pedigree         Age       Class
count   768.000000  768.000000  768.000000  ...  768.000000  768.000000  768.000000
mean      3.845052  120.894531   69.105469  ...    0.471876   33.240885    0.348958
std       3.369578   31.972618   19.355807  ...    0.331329   11.760232    0.476951
min       0.000000    0.000000    0.000000  ...    0.078000   21.000000    0.000000
25%       1.000000   99.000000   62.000000  ...    0.243750   24.000000    0.000000
50%       3.000000  117.000000   72.000000  ...    0.372500   29.000000    0.000000
75%       6.000000  140.250000   80.000000  ...    0.626250   41.000000    1.000000
max      17.000000  199.000000  122.000000  ...    2.420000   81.000000    1.000000

[8 rows x 9 columns]

  Dataframe headers:

Traceback (most recent call last):
  File "exercise4.py", line 152, in <module>
    exercise4 ( )
  File "exercise4.py", line 76, in exercise4
    for col in df.columns ( ):
TypeError: 'Index' object is not callable