Stat 555 Statistical Ecology

GUIDELINES FOR WRITING UP HOMEWORK ASSIGNMENTS

By explicitly following each step of an analysis and writing out your interpretation you will clarify thoughts that were previously unclear. For all assignments, include the following in your homework:

An abstract of your results: this should describe, in 1-2 paragraphs, what the goals of your homework were, what you did, what you found, and what it means.

In addition, the following information should accompany each statistical problem, and should be written directly on the output.

  1. Describe the problem. What was the purpose of the exercise and how were the data collected. Describe the experimental design and any variables that were uncontrolled (i.e., were samples obtained at different times).
  2. State a Null Hypothesis. In a single statement make a clear, concise null hypothesis. State it in two ways: in strict statistical terms, using parameters, and in scientific terms. (This step may not apply to all assignments)
  3. List the assumptions of the statistical analysis. Even though you may do this a hundred times do not skip this step! If any assumptions can be tested be sure to run the appropriate test prior to the main test and include it in the output.
  4. Determine the level of significance. This is always done prior to a test and is traditionally set at alpha = 0.05.
  5. Provide a statistical interpretation of the results. State a clear acceptance or rejection of the null hypothesis and list all of the statistics involved.
  6. Provide a scientific interpretation of the results. Using scientific terms state a clear explanation of the significance of the analysis. THIS is the most important part! Discussion should be focused on what you have learned from your analysis. What do your results mean? How can they be improved? Did you accept the null hypotheses because it is true or because your sample size was too low or the system too variable?

All of the above should be written in as few words as possible. One or two sentences is usually sufficient, except for the interpretation, which should be at least a paragraph (after all this is why we're doing it the first place)

NOTE ON WORKING TOGETHER ON ASSIGNMENTS: It is OK, and in fact I encourage you to work with your classmates on your homework. However, you should individually write up your assignments. If any homework assignments are reasonably identical neither party will receive credit for the assignment.