Hello!
3. How does temperature affect a football players performance?
Independent Variable: Temperature
<em>Temperature is the independent variable because that is what you are testing.</em>
Dependent Variable: Points scored in game
<em>Since you are attempting to measure how well football players do in different climates, you must measure their scores.</em>
Constants: Uniform, field played in, and ball used
<em>If you use a different uniform, field, or ball, then the data is obviously going to be inconsistent.</em>
Hypothesis: If football players are in colder climates, then they perform better during games.
<em>This is quite self-explanatory: just use the latter data points to craft your hypothesis. Keep in mind that a hypothesis should NEVER be a question!</em>
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I hope I helped! :-)