When should a line graph be used? A. When the independent variable is composed of categories and does not show a relationship.
B. When the independent variable is continuous and does not show a relationship to the dependent variable.
C. When there is no independent variable.
D. When the independent variable is continuous and shows a causal link to the dependent variable.

D. When the independent variable is continuous and shows a causal link to the dependent variable.

Explanation: Line graphs are usually very useful in visualizing relationships between variables (dependent and independent variable). Line graphs produce a very simple plot of these variables, however, by mere visualizing a line graph, one can tell if there exist a causal relationship between the measured variables. The independent variable when creating line graphs are real numerical values which should be continuous, aligning with the trend line produced by the graoh.

i just learnt this recently but i need to look through my notes again