Question

Independent vs. Dependent
• On average, do women perform better on their statistics
final than men?
• On average, is there a difference in people’s blood
pressure before and after giving a speech. 40 people’s blood
pressure was measured before and after giving a public
speech.
• At a specific restaurant, is the average tip percent greater
for supper than lunch? 35 wait staff who worked both lunch
and supper check their receipts and tips.
• On average, are Americans more stressed compared to the
French? 50 people from each country were given a stress
test.

Answer 1

In the context of the questions you've listed, we can identify independent and dependent variables based on the study designs:

1. **On average, do women perform better on their statistics final than men?**
- **Independent variable**: Gender (women vs. men)
- **Dependent variable**: Performance on statistics final (measured through grades or scores)

2. **On average, is there a difference in people’s blood pressure before and after giving a speech? 40 people’s blood pressure was measured before and after giving a public speech.**
- **Independent variable**: Time of measurement (before vs. after the speech)
- **Dependent variable**: Blood pressure readings

3. **At a specific restaurant, is the average tip percent greater for supper than lunch? 35 wait staff who worked both lunch and supper check their receipts and tips.**
- **Independent variable**: Meal time (lunch vs. supper)
- **Dependent variable**: Average tip percent

4. **On average, are Americans more stressed compared to the French? 50 people from each country were given a stress test.**
- **Independent variable**: Nationality (Americans vs. French)
- **Dependent variable**: Stress test scores

In summary, the independent variable is the one that is changed or controlled in an experiment, while the dependent variable is the one that is measured and affected based on the independent variable.