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Looking at Data  Relationships

Correlation
IPS Chapter 2.2
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View Full Document Objectives (IPS Chapter 2.2)
Correlation
The correlation coefficient “r”
r does not distinguish between x and y
r has no units of measurement
r ranges from 1 to +1
Influential points
The correlation coefficient "r"
The correlation coefficient is a measure of the
direction
and
strength
of a linear relationship.
It is calculated using the mean and the standard deviation of both
the
x
and
y
variables.
Correlation can only be used to describe
quantitative
variables.
Categorical variables don’t have means and standard deviations.
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View Full Document The correlation coefficient "r"
Time to swim: x = 35, s
x
= 0.7
Pulse rate: y = 140 s
y
= 9.5
involves finding z, the
standardized score we used
when working with the
normal distribution.
You DON'T want to do this by hand.
Make sure you learn how to use
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This note was uploaded on 03/10/2009 for the course ECON 1801232000 taught by Professor Brown during the Spring '09 term at UCLA.
 Spring '09
 Brown

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