The purpose of the procedure is for us to be able to decide if a possible explanation to particular things we see in nature actually is true. An investigation that is performed in a correct way should result in only two things: that we either keep the explanation as possibly correct or reject it as wrong. We can with confidence conclude that the explanation is incorrect when the result from our investigation is what was not predicted in the explanation. This result is expressed in our null hypothesis (see figure 1) and it should include a prediction of results from measurements, since most things in the living world for lots of reasons vary. Consequently the hypothesis states what measured values we should get, if the explanation is correct.
If the results agree with the null hypothesis it is not as the explanation predicted. In such a case, we keep the null hypothesis and reject the hypothesis and also the model in figure 1. The condition for keeping the model is when what the explanation predicts occurs. If the investigation gives results that agree with the hypothesis it accordingly happened what the explanation predicts. Then we reject the null hypothesis and have support for the model in figure 1.
Making one turn through this scientific process is not enough, an explanation must constantly be compared with others and subjected to critical examination.
Observations and explanations
|Arrange and understand|
|Observations and models|
|Hypotheses and predictions|