Correlation chart
properties | Configuring a Correlation
chart | Correlation chart
calculations

Correlation charts are used to plot linear relationships where
there is a correlation between two measures; that is, two measures
that tend to vary together. There is not necessarily causation
between the two measures. The Correlation chart can be used to
improve forecasts based on a strong correlation factor, or to show
that two measures do not have a strong correlation factor; that is,
they do not vary together.

One measure is plotted on the Y axis and the other measure is
plotted on the X axis. The actual data is plotted as a scatter
diagram. The regression line (the line that shows the trend of the
values) is the line in the middle that shows the correlation. A
perfect positive correlation is a 1:1 relationship and has a
correlation value of +1; a perfect 1:1 negative correlation has a
factor of -1. A strong correlation value would typically fall into
the range of 0.85 to 1 (or -0.85 to -1). A correlation value below
0.59 (or

-0.59) indicates a weak correlation.

The lines that frame the regression line are called confidence
bands and appear on either side of the regression line. The
confidence limit for the bands is configurable. The circular line
is called the prediction ellipse and shows a particular confidence
variation that you can set on the configuration dialog box.

In the following Correlation chart example, two variables are
compared (UnitPrice to UnitsInStock) and are plotted in a scatter
diagram. This chart shows the confidence bands (yellow), regression
line (green), and prediction ellipse (red).

### See Also