Much of ecological research involves making a decision. Does implementing a particular management strategy significantly increase the species diversity of a region? Is the amount of tree cover significantly associated with the number of deer? Do bigger individuals of a species tend to have longer life expectancies?
To answer these questions ecologists collect data and perform a statistical test, either explicitly or in the form of interpreting the significance of a coefficient (usually some sort of value relating to the effect of an environment variable, like temperature or pollution levels) in a model. The p-value is often used to help translate the results of a test or model into a decision. You’ve heard it over and over again: if the p-value is less than 0.05 we reject the null in favor of the alternative. But what does that really mean? What is the null? What is the alternative? And what is so special about 0.05?
What's the deal with p-values and their friend, the confidence interval?
February 13, 2020 | Ecology for the Masses