Give a brief overview of the questions you will be addressing and the context in which they arise. Usually two to four sentences is adequate
In this section, describe the nature of the data, where and how it was collected, how it came into your hands, etc. Since the conclusions that can be drawn from data usually depend critically on the way in which the data were collected, you must outline the characteristics of the study design well enough so that the appropriateness of your statistical methods and conclusions can be judged.
This section begins with a general approach to the problem of data analysis. Often, information about the data source will be incomplete, so your analysis has to be based on some reasonable assumptions concerning this missing information. This section is the right place to outline any assumptions that your analyses rely on.
The analysis proper will usually consist of one or more iterations of the following cycle: (a) develop a model for the data which can be used to answer the underlying question (or a part of it), (b) test the model against the data, (c) draw conclusions about the adequacy of the model and/or limitations in the data, and (d) decide whether changes to the model (either simplifications or refinements) are warranted. In brief,
At this point, you need to interpret what the data have to say about the question, in light of your modeling and data analysis. Describe the size of effects, the nature of systematic effects, and the strength of evidence. The results should always be expressed in terms of the original problem, not in terms of statistical significance. Remember, for instance, that the counts in a table are not numbers, they represent people, or plants, or viruses, or days spent in a hospital.
This section may be very brief, or may be the longest and most important section in the paper -- it depends on the problem, its importance, the data, and your analysis of it. This is the place to discuss such aspects of your analysis as its implications, to point out the sensitivity of your analysis to assumptions that you had to make about the context, the data, or the interpretation of the issues, to argue for conclusions that you believe are warranted by your analysis, and, perhaps, to outline further actions that might be appropriate.
This section contains the detailed information that a reader would need to locate supporting materials. These may include publications, or URLs of resources on the web. Each of the items in the reference list should be referred to explicitly in one or more of the sections above. The reference section is not a reading list.
Supporting details (such as annotated computer output) may be most effectively presented as an appendix. The body of the report itself should refer explicitly and precisely to the relevant portions of the appendix "See Appendix" is usually not adequate.