Why is it important to write a hypothesis in an “If this ..., then that…” format?

Answer 1

Because you are basing your hypothesis on some form of evidence that you are not going to try to prove in this statement.

For example: If the Earth is round (wich you won't try and prove), then you can orbit it (which you will try and prove.)

Answer 2

That is the foundation of the scientific method.
- First you propose a theory
- Then you test the theroy and if successful
- You publish the theory for others to test, called peir review.
- If sucessful then you theory will be accepted by the scientific community.

According to Wikipedia: http://en.wikipedia.org/wiki/Scientific_Method
"Scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. It is based on gathering observable, empirical and measurable evidence subject to specific principles of reasoning, the collection of data through observation and experimentation, and the formulation and testing of hypotheses.

Although procedures vary from one field of inquiry to another, identifiable features distinguish scientific inquiry from other methodologies of knowledge. Scientific researchers propose hypotheses as explanations of phenomena, and design experimental studies to test these hypotheses. These steps must be repeatable in order to predict dependably any future results. Theories that encompass wider domains of inquiry may bind many hypotheses together in a coherent structure. This in turn may help form new hypotheses or place groups of hypotheses into context.

Among other facets shared by the various fields of inquiry is the conviction that the process must be objective to reduce a biased interpretation of the results. Another basic expectation is to document, archive and share all data and methodology so it is available for careful scrutiny by other scientists, thereby allowing other researchers the opportunity to verify results by attempting to reproduce them. This practice, called full disclosure, also allows statistical measures of the reliability of these data to be established."