In the context of scatterplots and linear associations, the description that indicates the "weakest positive linear association" would be:
"On a graph, points are grouped closely together and increase."
This option suggests that the points show an upward trend but are not described as forming a distinct line, implying the association is less strong compared to the option where points are grouped closely together to form a line and increase.
In summary, the scatterplot showing points that increase but are not tightly clustered along a line (the first option) would indicate the weakest positive linear association compared to a stronger, more linear formation.