Reports

The purpose of a statistical report is to communicate the results of a statistical analysis is a clear, succinct way. A good statistical report will:

Additionally, the report should be fully reproducible, such that if the reader had the data, they could recreate your results exactly.

An example research question

Between 1968 and 1972, researchers injected massive amounts of silver iodide into cumulus clouds in Southern Florida, in hopes of investigating whether the “seeding” of clouds can lead to increased rainfall.1 The following summary of the study is provided in the Statistical Sleuth:

On each of 52 days that were deemed suitable for cloud seeding, a random mechanism was used to decide whether to seed the target cloud on that day or to leave it unseeded as a control. An airplane flew through the cloud in both cases, since the experimenters and the pilot were themselves unaware of whether on any particular day the seeding mechanism in the plane was loaded or not (that is, they were blind to the treatment). Precipitation was measured as the total rain volume falling from the cloud base following the airplane seeding run, as measured by radar. Did cloud seeding have an effect on rainfall in this experiment? If so, how much?

This question may be answered using a two-sample t-test, a topic covered late in this course. For now, let’s take a look at what a good statistical report might look like for this research question.

In particular, please note:

  • the clear statement of the research question and data collection strategies
  • the description and visualization of the raw data
  • clearly articulated statistical procedure
  • assumptions of that procedure
  • succinct statement of the results
  • scope of inference
  • code appendix

Resources

The following resources may be helpful:

Footnotes

  1. Simpson, J., Olsen, A., and Eden, J.C. 1975. “A Bayesian analysis of a multiplicative treatment effect in weather modification.” Technometrics↩︎