Match the Research Examples in 1-7 with the Main Threat

Multiple Choice

Match the research examples in 1-7 with the main threat to internal validity that it contains (a-g) .
-At the start of the school year, the mathematics achievement of a group of young children is assessed. They are then all exposed to a new mathematics program and re-examined at the end of the school year.

A) Maturation
B) History or environmental events
C) Repeated testing
D) Instrumentation
E) Selection or assignment
F) Mortality or attrition
G) Statistical regression