Microsoft Office Tutorials and References
In Depth Information
Fig. 6.5 Example of a Scatterplot for a Moderate, Negative Correlation (r
¼
.39)
Fig. 6.6 Example of a Scatterplot for a Perfect, Negative Correlation (r ¼ 1.0)
Fig. 6.5 ). In this case, it is a negative correlation because the “football” you could
draw around the data points slopes down and to the right.
Fig. 6.6 shows a perfect negative correlation of r
1.0 which means that X is
a perfect predictor of Y, although in an inverse relationship such that as X increases,
Y decreases. The data points ﬁt perfectly along a downward-sloping straight line
(see Fig. 6.6 )
Let’s explain the formula for computing the correlation r so that you can
understand where the number summarizing the correlation came from.
In order to help you to understand where the correlation number that ranges from
¼
þ
1.0 comes from, we will walk you through the steps involved to use the
formula as if you were using a pocket calculator. This is the one time in this topic
1.0 to
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