Consider the data forbes.data, which gives ancient numbers for a sample of fortune 500 companies (at the time). The response variable is Sales and of particular interest is whether the sector variable has any effect.

1. Do any of the variables need to be transformed to ensure a proper analysis? If so, make the appropriate transformations.
2. After this, compute the variance inflation factors for each of the X variables.
3. Build (an) appropriate model(s) for Sales. Pay attention to transformations, variable selection, and outliers. Does sector have an effect?