For each of the following research projects, please indicate both independent variables and then specify the levels of each independent variable. Use the information to draw a design matrix and give the numerical label to the design (e.g., 2 × 3)

1. Edguer and Hardy investigated the effects of musical training on memory. Based on the length of musical training, the participants were categorized as novice, intermediate, or expert musicians. Half of the participants had words presented aurally, and half had words presented visually. The number of words recalled was recorded.

2. Allen investigated the influence of schizophrenia and substance abuse on memory. All participants took a 30-item memory test. He compared schizophrenics with non-schizophrenics, and within each group, he compared nonusers with alcoholics and with cocaine users.