Exercise

# Specify a linear model to compare 2 groups

To identify differentially expressed genes for the leukemia experiment, you need to translate the following linear model to R:

where \(X_{1}\) is equal to **1** for progressive cancers and **0** for stable cancers (note: R automatically chooses the base condition by alphabetical order).

Instructions

**100 XP**

The ExpressionSet object `eset`

with the leukemia data has been loaded in your workspace.

- Use
`model.matrix`

to construct a design matrix with an intercept coefficient and a coefficient that indicates the disease status.