________ threats to internal validity occur whenever,at the start of the experiment,the test and control groups differ in terms of relevant demographics,attitudes,or behaviors.
A)Testing
B)Mortality
C)Researcher bias
D)Selection
E)Premeasurement

Question

Quizplus · Accepted Answer

Selection threats occur when there is a bias in the assignment of participants to the experimental and control groups. This can occur when participants self-select into groups or when there is non-random assignment by the researcher. If the groups differ at the start of the study, it may be difficult to determine whether any differences in outcomes are due to the experimental manipulation or pre-existing group differences.

________ Threats to Internal Validity Occur Whenever,at the Start of the Experiment,the