Final answer:
Variables can have positive, negative, or zero correlation. Number of children and diaper expenses would have a positive correlation, interest rates and number of cars sold would have a negative correlation, hours on the treadmill and cholesterol levels may have zero correlation, and the price of a Big Mac and the number of fries sold may have no correlation.
Step-by-step explanation:
The correlation between variables can be positive, negative, or zero. A positive correlation means that the variables move in the same direction, so as one variable increases, the other variable also increases. For example, the number of children in the household under the age of 3 and expenditures on diapers would have a positive correlation, as more children would likely lead to higher diaper expenses.
A negative correlation means that the variables move in opposite directions. For instance, interest rates on car loans and the number of cars sold would have a negative correlation, as higher interest rates would discourage people from buying cars.
A zero correlation means that there is no relationship between the variables. Therefore, the number of hours per week on the treadmill and cholesterol level may have zero correlation, indicating that the amount of time spent on the treadmill does not affect cholesterol levels.
Lastly, the price of a Big Mac and the number of McDonald's French fries sold in a week may have no correlation, as the price of a Big Mac does not directly impact the demand for French fries.