A Team of Researchers Conduct a Study in Which They

Multiple Choice

A team of researchers conduct a study in which they want to look at how the performance of children from the worst-performing school in the country is affected by a change in government education policy.Looking at a new sample of students, they find that a year later the school is no longer the worst-performing and attribute this to the effects of the policy.Which of the following is most likely to affect the internal validity of this conclusion?

A) Mortality effects.
B) Regression to the mean.
C) Practice effects.
D) Demand characteristics.
E) Experimenter bias.