In Order to Conduct an Experiment More Efficiently,a Researcher Tests

Multiple Choice

In order to conduct an experiment more efficiently,a researcher tests groups of participants in several small groups.The number of participants in each group differs because of participants' availability at different times.The different number of participants in each group represents a potential

A) intact group problem.
B) selective subject loss problem.
C) experimenter effect.
D) extraneous variable problem.