Question

He then asks both groups to take notes in the exact same way to see how it will affect their scores. During the study, several students in the low-achieving group drop out from the study, as they find the note-taking task difficult. At the end of the study, the results for each group are similar.

Answer 1

selection attrition threat

Step-by-step explanation:

Selection attrition threat refers a situation when the subjects of the research fail to complete their tasks before the researchers finished in collecting the data. (in the case above, some of the participants drop out from the study before finishing it)

Since we can't really obtain the full results from the subjects, the researchers will create a threat to the internal validity of the research if they draw a conclusion with the incomplete data.