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Lesson 2:  Looking at Data:  Relationships

Contents

This lesson covers ...

• Objectives
• Key Terms
• Reading Assignment
• Internet Links
• Study Questions
•  Study Notes
• Written Assignment

Objectives

After completing this lesson, you should be able to:

1. Construct and interpret graphical displays of the relationship between two continuous or categorical variables.
2. Compute and interpret appropriate numerical summaries of a relationship.
3. Use the tools of linear regression and correlation to describe important features of a relatioship.

Reading Assignment

Read Chapter 2 in the text.

• Datamining article Minneapolis Star-Tribune article on a hot, new area of statistics.

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Key Terms

• Relationship
• Scatterplot
• Outlier
• Bar Graph
• Linear Correlation
• Linear Regression
• Causal Relationship
• Slope
• Intercept

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Internet Links

Each day you go online, be sure to check out the Random Statistical Quote for the Day
  Investigate the following examples from other Internet sites:

• Statsoft's Site Take a look at linear regression.
• UCLA Electronic Text  Take a look at the correlation presentation.
• UCLA XLISP-STAT Demos.  Examine Section 1, modules 1 and 2.  You will need to set up the software xlispstat to be a helper application to do these.  Follow instructions on this page to get xlispstat and to designate it as a helper application.   These modules are very cool.  It is worth getting the software and doing all the setup.
• Two continuous variables from SurfStat.australia  Explore the two continuous measurements material.
• Correlation and Regression from SurfStat.australia  Explore the correlation and regression material.

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Study Questions

1. What would be a good graphical display to help you predict human weight if you know the height?
2. What would be a good graphical display to help you understand the relationship between gender and marital status?
3. If I can tell you the value of the response variable perfectly if you tell my the predictor, does this mean that the correlation is 1?
4. What is an outlier in a scatterplot?
5. What impact can an outlier have on least squares regression lines?

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ACTIVITIES

SIMPSON'S PARADOX

SPURIOUS CORRELATION CONTEST

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Study Notes

Lecture notes Lecture notes from Chapter 2 in Acrobat format.

This format has been too slow and cumbersome on my computer, if you have the same experience, try the html version of the notes in the link below.

Lesson 2 notes Lesson 2 notes in html format, probably easier to read and deal with.

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Statistics Computing

STATLETS Program Link

STATLETS Examples/Help Page

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Written Assignment

Do the following assignment. The problems listed are from the textbook in chapter 2. Once you have worked on the problems and are ready to turn in your findings, click the assignment link below. It will take you to a template where you can fill in your answers to the questions. When you are finished entering your answers, click the submit button, you will be given the location of your completed web page.  You may check your assignment responses with your browser at any time, and submit a revision at any time before the due date of the assignment. However, when you submit a revision, all previously submitted work will be overwritten.

Lesson Submission 2

Due on Monday July 26, 1999 ()

Text problems 2.5, 2.6, 2.21, 2.38, 2.39, 2.45, 2.52, 2.89, 2.102

Assignment #2.

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