Video Transcript
What type of correlation exists between the two variables in the following scatter graph?
We know that a scatter graph represents bivariate data and that the correlation can be positive, negative, or there can be no correlation. In order to identify this, we can draw a line of best fit as shown. This shows us the general pattern of the data points. Generally, this line of best fit is then used to predict the value of one variable given the other.
In this question, our line of best fit is a vertical line, and it intersects the 𝑥-axis at 𝑥 equals six. This value of 𝑥 equals six represents the whole range of 𝑦-values. Knowing the value of one variable will therefore not enable us to predict the value of the other variable. We can therefore conclude that when a scatter graph has a vertical line of best fit as in this question, there is no correlation between the two variables.
