For a high school project, I investigated the effect of breathing meditation on teenagers. 15 students were asked to follow specific directions and meditate for 10 minutes a day for 8 weeks. Each week, their heart rate, ventilation rate, maximum lung capacity and blood pressure were measured with 5 trials. These measurements were also done prior to the meditation regimen.

My question is, to publish an experiment in a scientific paper, must there be a specific number of participants, trials, or time-length of the experiment? This is to talk about in the discussion part of my report.

Please let me know what you know!

  • $\begingroup$ Based on the complaints that have been made on my questions, this question might get attacked as being off topic. $\endgroup$ Dec 23, 2017 at 13:20
  • 1
    $\begingroup$ @DanielGoldman — "attacked"? I think you should choose your words a little more carefully. The SE system allows users with a certain ‘reputation’ to review questions and vote to close them if they are regard them as off-topic in the terms defined by SE Biology. This is not ‘attacking’ but is performing a public duty to help maintain the standards of the site (you can get badges for it). So, yes, I do consider this probably off topic, but no, I haven‘t voted to close as I thought it wouldn‘t hurt for someone to answer this young person. $\endgroup$
    – David
    Dec 23, 2017 at 17:12
  • $\begingroup$ one important thing to consider would be to compute the statistical power of your experiment. There are online calculators, e.g. here, but it does sometimes take some creativity/adjustment to match your experimental design with the numbers the calculator is expecting. The most important thing is that you need to pick an effect size that you are expecting. (This is arguably more of a statistical question, e.g. for Cross Validated rather than Biology SE) $\endgroup$
    – Ben Bolker
    Dec 24, 2017 at 17:36

1 Answer 1


There is no single measure for "robustness" and a lot of it boils down to the field. Usually physics has a very high degree of precision: p value close to 0. For instance, the Higgs boson was a confidence level of 5 sigma, while biology or psychology is going to usually have more leeway: maybe 2 sigma (Sigma).

However, there should be no (statistical significance) criterion to publish. The idea that only positive studies should be published has led to biases in available data in a number of fields (Fighting publication bias: introducing the Negative Results section). Negative results are very useful to us as robustness of a theory is often evaluated using meta-analyses. If a person fails to publish their results because it does not robustly justify their theory, then the data available to perform a meta-analysis is diminished.

Clearly, you want the study to be properly run and you want the method to be reasonable. A garbage study, regardless of the statistical significance measured, is going to be looked upon negatively.

That being said, if your topic is something that has been researched a number of times, a small study is not going to be looked at very well, as there is already "better" information available. The study should provide some kind of new insight into the topic.

  • $\begingroup$ “p values close to 1”? I think there is at least a 0.00 missing from your answer. $\endgroup$
    – David
    Dec 23, 2017 at 17:15
  • $\begingroup$ Yeah; should be really close to 0, not 1. Sorry. Corrected. $\endgroup$ Dec 23, 2017 at 17:41

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