The scientific method as described here is an idealization, and should not be understood as a set procedure for doing science.
If an experiment disagrees with the current theory, the theory has to be changed, not the experiment. You will then present your thesis statement in your introduction, prove it with evidence in the body of your paper, project, or presentation, and finally restate it along with a summary of your evidence in your conclusion.
Write down the conclusions of your scientific test or experiment.
Explanatory value means that many phenomena should be accounted for with few basic principles. The statement can be restricted or clarified and eventually worked into an introduction. Ask these questions: What is it?
A thesis statement is focused and specific enough to be proven within the boundaries of the paper.