1. Investigating associations between two variables
12 Further mathematics
Investigating associations between two variables

2. Investigating associations between two variables
When investigating associations between variables, it is helpful to think of one of the variables as the explanatory variable. The other variable is then called the response variable. We use the explanatory variable to explain changes that might be observed in the response variable.
For example, the question, ‘Does a person’s attitude to gun control depend on their sex?’, suggests that knowing a person’s sex might be useful in explaining their attitude to gun control. In this situation sex is the explanatory variable and attitude to gun control is the response variable.
It is important to be able to identify the explanatory and response variables before you explore the association between them. Consider the following examples.

3. Investigating associations between two variables

4. Investigating associations between two variables
It is important to note that, in Example 2, we could have asked the question the other way around; that is, ‘Can we predict people’s wrist measurement from their height?’ In that case height would be the explanatory variable, and wrist measurement would be the response variable. The way we ask our statistical question is an important factor when there is no obvious explanatory variable.

5. Investigating associations between two variables

6. Exercise 3A All Questions
WORK TO BE COMPLETED
Exercise 3A All Questions