Exercise

Design matrix for 3 groups

In the hypoxia experiment, stem cells were exposed to 3 different levels of oxygen: 1%, 5%, and 21%. To contrast the cellular function in these 3 different environments, use the group-means parametrization to specify a linear model with a coefficient for each level of oxygen.

Instructions

100 XP

The ExpressionSet object eset with the hypoxia data has been loaded in your workspace.

Use model.matrix to create a design matrix with no intercept. Recall that the variable of interest for this study (3 oxygen levels) is in the column oxygen of the phenotype data frame.