A hypothesis is a prediction about the outcome of an experiment based on current assumptions and the requirement that certain conditions exist. Let's break down the definition into simpler terms. A prediction is what the researcher believes the results of the experiment are going to be. For example, a researcher might predict that bleach and brushing are going to be the best combination for removing the Kool-Aid and the mustard stains. Another prediction may be that washing alone will not remove the stains.
Many times beginning researchers stop there when making a hypothesis.
However, a hypothesis needs to include assumptions and conditions. Assumptions are those things that you believe to be true. Assumptions are based on your previous experiences. An assumption that may be made by a researcher is that all of the solvents will be able to remove at least some of both stains. Conditions are things that have to take place in order for the predicted results to occur.