Statistics and Data Analysis for Microarrays Using R and Bioconductor, 2nd Edition

446 Statistics and Data Analysis for Microarrays Using R and Bioconductor

14.5.2.1 One-way Model I ANOVA

We will start with an example of a one-way Model I ANOVA. Let us consider

Example 13.3 discussed in Chapter 13. In this example, the expression level

of a gene is measured in three types of mRNA sources (mRNA1, mRNA2,

mRNA3) using five different arrays:

Array

mRNA 1 mRNA 2 mRNA 3

1 100 95 70

2 90 93 72

3

105 79 81

4 83 85 74

5 78 90 75

We are interested in any difference between the three mRNA sources,

henceforth called groups. The preferred way to organize the data for linear

modeling is within a data frame, in which the gene expression level y, as

well as ...