Which of the Following Is an Example of Nonexperimental Research

Multiple Choice

Which of the following is an example of nonexperimental research?

A) A researcher manipulates how students are taught statistic and then looks at the performance differences on a posttest
B) A researcher manipulates how students are taught to solve word problems and compares math performance on a test
C) A researcher looks at the correlation between reading speed and reading comprehension
D) A researcher assigns students with ADHD to one of two drug treatment groups and examines the impact of the drug conditions on ADHD symptoms