An engineer tries three different methods for selecting a linear model. First she uses an informal method based on the F statistic, as described in Section 8.3. Then she runs the best subsets routine, and finds the model with the best adjusted R2 and the one with the best Mallows Cp. It turns out that all three methods select the same model. The engineer says that since all three methods agree, this model must be the best one. One of her colleagues says that other models might be equally good. Who is right? Explain.

Introduction: Week 1: How do we define mental illness DSM-5- The diagnostic and statistical manual of mental illness. The DSM-5 is the eighth version and the first to not use roman numerals. The first DSM was created in 1952 and included 90 pages; while the DSM-5 has 980. It is revised by a voting committee who discuss each illness and vote on whether one should be added or dropped....