Here's what makes a hypothesis testable:
* Measurable Variables: The variables involved must be measurable or observable. You need to be able to quantify or qualify them in some way. For example, "Plants grow taller in sunlight" is testable because you can measure plant height and control the amount of sunlight. "Ghosts cause haunted houses" is not testable because "ghosts" and their effects aren't easily measurable or observable in a controlled way.
* Falsifiable: A testable hypothesis must be able to be proven wrong. If there's no possible outcome that would disprove it, it's not testable. A hypothesis stating "Plants *might* grow taller in sunlight" is weak because many things *might* happen, but it doesn't offer a specific, falsifiable prediction.
* Specific and Clear: A testable hypothesis is clear, concise, and unambiguous. Vague or overly broad statements are difficult to test. For example, "Exercise is good for you" is too broad. A better, testable hypothesis would be "Individuals who engage in 30 minutes of moderate-intensity exercise daily will show a decrease in blood pressure compared to those who do not."
In short, a testable hypothesis allows you to design an experiment or study that can produce evidence to either support or reject the proposed relationship between variables. If you can't design a test, it's not a testable hypothesis.