Connected to Stuff that maes Stuff happen. A null hypothesis could be one where obesity, exercise and internet are not connected, or alternatively that exercise (or lack thereof) causes obesity, and internet is unrelated to both of these. Then, you can conduct an experiment and collect evidence for or against the null hypothesis. If p=P(data | null hypothesis is true)<0.05, a winner is you.
Connected to Stuff that maes Stuff happen. A null hypothesis could be one where obesity, exercise and internet are not connected, or alternatively that exercise (or lack thereof) causes obesity, and internet is unrelated to both of these. Then, you can conduct an experiment and collect evidence for or against the null hypothesis. If p=P(data | null hypothesis is true)<0.05, a winner is you.