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20 sie 2020 · Example 1: LTEs with monocultures or perennial crops. Wheat is grown in continuous cropping from 1983 to 2012, with three fertilisation levels (150, 200 and 250 kg N ha \(^{-1}\)), randomly assigned to three plots in each of three blocks. In all, there are nine plots with yearly sampling, with a total of 270 wheat yield observations in 30 years.
Let’s develop an example to see how an ANOVA is done. An experiment in northwest Iowa compared the yield of a corn hybrid planted at three plant densities to determine the optimum planting rate. The data are given in Table 1.
Using ANOVA, especially if the experiment had the treatments arranged in a factorial arrangement, is a good approach to test for treatment effects and interactions. Fertilizer rate main effects can be subjected to polynomial contrasts, a statistical method to determine if there are linear or quadratic components in the overall response.
For example, an experiment with several different varieties of a crop and several different fertilizer treatments could use main plots for the fertilizer treatments and sub-plots within main plots for the individual varieties.
In this article, we’ll guide you through what ANOVA is, how to determine which version to use to evaluate your particular experiment, and provide detailed examples for the most common forms of ANOVA.
2 sty 2023 · Load the greenhouse data. Produce a boxplot to plot the differences in heights for each species organized by fertilizer. Produce a “means plot” (interval plot) to view the differences in heights for each species organized by fertilizer. Obtain the ANOVA table with interaction.
2 sty 2023 · Produce a boxplot to plot the differences in heights for each fertilizer. Produce a "means plot" (interval plot) to view the differences in heights for each fertilizer. Obtain the ANOVA table. Obtain Tukey’s multiple comparisons CIs and difference in means plot. Produce diagnostic (residuals) plots.
