Students cannot use data from graphs to support explanations if they cannot read the graph so it is important to check that they can do that. It is also important that students become aware that there could be more than one explanation for trends they see in the data. Sometimes it is important to suspend judgement until there is enough data.
Developing an appreciation of what counts as evidence in science supports students to become scientifically literate, i.e., to participate as critical, informed, and responsible citizens in a society in which science plays a significant role. (This is the purpose of science in NZC.)