An Educational Researcher Has Designed Two Different Methods for Teaching

Multiple Choice

An educational researcher has designed two different methods for teaching a statistics course and would like to investigate which is more effective.He designs an experiment as follows.He will obtain a group of volunteer statistics students.Volunteers will be randomly assigned to one of two groups.Group 1 will be taught the statistics course by Anna Clark using method A and group 2 will be taught by Bob Beauman using method B.At the end of the semester,students will all take the same test.Then the scores for the two groups will be compared.The person grading the tests will be blinded to which group students were in.Identify the most serious flaw in this experiment.

A) There is a confounding variable - namely the teacher.
B) There is no blocking.
C) The person grading the tests may have been biased.
D) Since there is no random assignment,there could be lurking variables.
E) Volunteers should have been selected randomly.