Question

1. An agricultural scientist wants to determine how the type of fertilizer and the type of soil affect the yield of oranges in an orange grove. He has two types of fertilizer and three types of soil. For each of the combinations of fertilizer and soil, the scientist plants four stands of trees, and measures the yield of oranges (in tons per acre) from each stand. The data are shown in the following table.

	Soil Type 1	Soil Type 2	Soil Type 3
Fertilizer A	20 24 22    9	22 22 27 25	29 25 23 28
Fertilizer B	23 23 30 24	23 29 31 32	25 29 30 31

Analyze the data using R. Conduct hypothesis tests using a=.05. Construct profile plot. Perform multiple comparisons if necessary. Construct normal probability plot of the residuals to assess the reasonableness of the normality assumption. Construct plot of residuals vs. predicted values to assess the reasonableness of the equal variance assumption.

Answer 1

First make data like that in Excel then Import in R.

Using R:

Here in B-A significant different.