Page 295 - Statistics for Dummies

Chapter 18
Looking for Links:
Correlation and Regression
In This Chapter
▶ Exploring statistical relationships between numerical variables
▶ Looking at correlation and linear regression
▶ Making predictions based on known relationships
▶ Considering correlation versus causation
oday’s media provide a steady stream of information, including reports
Ton all the latest links that have been found by researchers. Just today I
heard that increased video game use can negatively affect a child’s attention
span, the amount of a certain hormone in a woman’s body can predict when
she will enter menopause, and the more depressed you get, the more choco-
late you eat, and the more chocolate you eat, the more depressed you get
(how depressing!).

Some studies are truly legitimate and help improve the quality and longevity
of our lives. Other studies are not so clear. For example, one study says that
exercising 20 minutes three times a week is better than exercising 60 minutes
one time a week, another study says the opposite, and yet another study says
there is no difference.
If you are a confused consumer when it comes to links and correlations, take
heart; this chapter can help. You’ll gain the skills to dissect and evaluate
research claims and make your own decisions about those headlines and
sound bites that you hear each day alerting you to the latest correlation.
You’ll discover what it truly means for two variables to be correlated, when a
cause-and-effect relationship can be concluded, and when and how to predict
one variable based on another.

3/25/11 8:13 PM
26_9780470911082-ch18.indd 279 3/25/11 8:13 PM
26_9780470911082-ch18.indd 279