7.2. Suggestions

The study of normal galaxies will remain exciting because of, and in spite of, the complexities and bewildering abundance of data and correlations. A few suggestions might help in navigating these complexities:

1. In statistical studies, it is critical to understand the sample being used, its biases and limitations.
2. The questions to pursue should be physical rather than statistical in nature. The latter will flow from the former, but should not overshadow them.
3. Quantities studied, statistically or in detail, should have clear physical significance. Distance-independent ``intensive'' quantities are preferable to luminosities or similarly scaling extensive parameters.
4. In constructing quantities from observables, one should avoid complex parameters with multiple built-in assumptions, such as dust mass which combines a flux with an uncertain color temperature taken to a power of 5 or so.