Microsoft Office Tutorials and References
In Depth Information
(actually it is 82.48), the result above for predicting the
number of eggs produced from a fish weighing 3,500 g.
For a more detailed discussion of regression, see Black (Black 2010 ) and Gould
and Gould ( 2002 ).
6.6 Adding the Regression Equation to the Chart
Objective: To Add the Regression Equation to the Chart
If you want to include the regression equation within the chart next to the
regression line, you can do that, but a word of caution first.
Throughout this topic, we are using the regression equation for one predictor
and one criterion to be the following:
Y ¼ a þ bX
ð 6 : 3 Þ
where a = y-intercept and b = slope of the line
See, for example, the regression equation in Sect. 6.5.3 where the y-intercept
was a = 24.73 and the slope of the line was b = +0.0165 to generate the
following regression equation:
Y ¼ 24 : 73 þ 0 : 0165 X
However, Excel 2010 uses a slightly different regression equation (which is
logically identical to the one used in this topic) when you add a regression
equation to a chart:
Y ¼ bX þ a
ð 6 : 4 Þ
where a = y-intercept and b = slope of the line
Note that this equation is identical to the one we are using in this topic with the
terms arranged in a different sequence.
For the example we used in Sect. 6.5.3 , Excel 2010 would write the regression
equation on the chart as:
Y ¼ 0 : 0165 X þ 24 : 73
This is the format that will result when you add the regression equation to the
chart using Excel 2010 using the following steps:
Open the file: eggs36 (that you saved in Sect. 6.5.2)
Click just inside the outer border of the chart in the top right corner to add the
‘‘gray border’’ around the chart in order to ‘‘select the chart’’ for
changes you are about to make
Right-click on any of the data-points in the chart
Highlight: Add Trendline
The ‘‘Linear button’’ near the top of the dialog box will be selected (on its left)
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