Database Reference
In-Depth Information
REVIEW QUESTIONS
1) What are some of the limitations of correlation models?
2) What is a correlation coefficient? How is it interpreted?
3) What is the difference between a positive and a negative correlation? If two attributes have
values that decrease at essentially the same rate, is that a negative correlation? Why or why
not?
4) How is correlation strength measured? What are the ranges for strengths of correlation?
5) The number of heating oil consuming devices was suggested as a possibly interesting
attribute that could be added to the example data set for this chapter. Can you think of
others? Why might they be interesting? To what other attributes in the data set do you
think your suggested attributes might be correlated? What would be the value in knowing
if they are?
EXERCISE
It is now your turn to develop a correlation model, generate a coefficient matrix, and analyze the
results. To complete this chapter's exercise, follow the steps below.
1) Select a professional sporting organization that you enjoy, or of which you are aware.
Locate that organization's web site and search it for statistics, facts and figures about the
athletes in that organization.
2) Open OpenOffice Calc, and starting in Cell A across Row 1 of the spreadsheet, define
some attributes (at least three or four) to hold data about each athlete. Some possible
attributes you may wish to consider could be annual_salary, points_per_game,
years_as_pro, height, weight, age, etc. The list is potentially unlimited, will vary based on
the type of sport you choose, and will depend on the data available to you on the web site
you've selected. Measurements of the athletes' salaries and performance in competition are
 
 
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