Video Transcript
What type of correlation exists between the two variables in the following scatter graph?
We know that a scatter graph is a way of representing bivariate data, where each value of one of the variables is paired with a value of the other variable. One way of identifying a correlation is by drawing a line of best fit. We know that if our line of best fit slopes upwards from left to right, we have a positive correlation. And if the line of best fit slopes downwards from left to right, we have a negative correlation.
In some cases, as in this question, it is impossible to draw a line of best fit. If we consider the four points circled, we see that high values of 𝑥 correspond to both high and low values of 𝑦. Likewise, low values of 𝑥 correspond to both high and low values of 𝑦. We can therefore conclude that there is no correlation between the two variables in the scatter graph. If we know the value of one of our variables, it will not help us predict the value of the other variable.
