Analyze the trend line to describe the strength and the direction of the relationship.
Let's analyze an example to better understand this procedure.
Example
Let's assume that we want to describe the relationship between the two example data sets that consist of measurement data.
x
0.5
1.1
1.5
2
2.5
3
3.5
4
4.4
5
y
0.4
1
1.7
1.8
2.7
2.7
3.45
4.15
4.3
5
First we will plot the ordered pairs in a coordinate plane to create a scatter plot.
We can see that points form a line and this means that the association is linear. Because the relationship is linear, we can try to draw a trend line. Remember that this line should pass through the middle of the plotted points.
Looking at the graph, we can see that the y-values increase as x-values increase. In other words, the trend line has a positive slope. This means that the relationship between the data sets is positive. Also, the points are located close to our trend line, which means that the relationship is rather strong.
