4. Main Effects Charts

Main effects are defined as “the change in response when going from low level to high level”.

Example:

An agronomist is interested in investigating the effect of nitrogenated fertilization at two levels (N0 and N1) in a given cultivating. we will do the upload data to the system.

Nitrogen	Answer
N0	1.0
N0	1.2
N0	1.3
N0	1.6
N0	1.3
N1	1.5
N1	1.1
N1	1.6
N1	2.3
N1	1.4

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Configuring according to the figure below we will graph the main effects.

Then click Calculate view the results. You can also download them in a Word document.

The results are:

Confidence interval of the Effect Nitrogen

Level	Lower limit	Mean Effect	Upper limit
N0	0.92	1.28	1.64
N1	1.22	1.58	1.94

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