In an educational setting, a hypothesis, according to the Merriam-Webster Dictionary, is a guess made in order to verify, logically or scientifically, a certain idea or phenomena. It is worded as a statement, or as an answer to a question. Here is an example of one: "Sunlight is necessary for plant growth." The question associated with this would be: "Is sunlight necessary for plant growth?"
Forming a hypothesis begins with observing conditions, organisms or phenomena in our environment and formulating an opinion about how things work and the reasons for their behavior. It is important that no guesses be made at this point in the process. Guesses made without the proper research and background information will result in clouding the observer's judgment and having her come to a false conclusion.
Once an observation has been made, this warrants further investigation. The next step in formulating a hypothesis involves reading previous research on the topic. For example, if you have noticed that some orchids bloom earlier than others, you must first read up on what other botanists have reported on the matter, if anything at all. Hypotheses must be grounded in previously proven or disproven hypotheses, and a literature search is what ensures the basis of a hypothesis.
Once the background literature on the topic has been combed through, you can state the problem and formulate your answer to it as your hypothesis. Sticking with the orchid example from above, you can say something like: "Why do some orchids bloom earlier than others?" Your hypothesis would be something like: "Some orchids bloom earlier than others because of the amount of sunlight they are exposed to."
Your hypothesis is far from a wild guess. If all the research has been done, you have educated yourself on the topic and have eliminated some possible explanations based on your knowledge of previous findings. By forming a hypothesis, you have also set up a system with which you will come to a new fact about an observable entity in our environment.
A hypothesis is an educational guess because it encourages observation, research and contribution of knowledge about the world. In short, it is by formulating hypotheses about the things and phenomena around us that we learn about the world in a more comprehensive way than just passively guessing at what's going on.