What is the most likely problem for a randomized experiment that ...

[madam-professor]

What is the most likely problem for a randomized experiment that uses volunteers?

Question 2

If a statistically significant relationship is found in an observational study for which the sample represents the population of interest, then which of the following is true?
 a. A causal relationship cannot be concluded and the results cannot be extended to the population.
  b. A causal relationship can be concluded but the results cannot be extended to the population.
  c. A causal relationship cannot be concluded but the results can be extended to the population.
  d. A causal relationship can be concluded and the results can be extended to the population.

[ally]

Answer to Question 1

A common problem for experiments that use volunteers is extending results inappropriately. Common sense should enable you to figure out whether the volunteers in the study are representative of a larger population for that question.

Answer to Question 2

C