The hyphotesis
Figure 1.10: The hyphotesis
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The third step in the scientific method for solving a problem is to define the hypothesis.
Once you have a clear question, and you are relatively certain that no one has asked the question before, or answer it insufficiently, you should move to the next phase of the scientific method, which is to formulate your question more specifically. It could be as simple as:
Does Mycorrhizae increase the body size of plants?
For the purpose of the scientific method you need to be very specific in what you want to study. See for instance, how the question is explicit about fungi, affecting specifically the body size of plants. There are a few other nuances about formulating a question, that we will talk about when we deal with designing the experiment.
You could also reformulate your very specific question in the form of an hypothesis, like:
Mycorrhizae has a significant positive effect on the body size of plants
You should now note in the hypothesis version of the question that you now include an expectation that the effect will be positive. The other addition in the hypothesis is the word “significant”, meaning that any effect you find is “considerably” larger than the effect you would find if you were not to use Mycorrhizae.
Mathematically, the hypothesis has to be defined between two alternatives you can choose from: 1) the “Null hypothesis” and 2) the “Alternative hypothesis”.
The null hypothesis H0
The null hypothesis is denoted by the symbol H0. It commonly represents a statement of “no effect,” “no difference”.
In the restoration example,
H0 is Mycorrhizae has no significant effect on the body size of plants
The alternate hypothesis H1
The alternate hypothesis is denoted by the symbol H1. It commonly represents any hypothesis that differs from the null hypothesis. It should be defined in such a way to be accepted only when the null hypothesis is rejected.
In the restoration example,
H1 is Mycorrhizae has a positive significant effect on the body size of plants.