Question

Suppose that you want to measure the causal effect of hours spent studying on the performance on a microeconomics test for a class of 30 students.

Which of the following could be an ideal randomized controlled experiment to study the desired causal​ effect?

A.

Allow the fifteen students with the highest grades in the class an extra day to study for the microeconomics test. Then measure the test score differences between students who got the extra day to study and those that did not.

B.

Allow all students an extra day to study for the microeconomics test. Then measure the test score difference between the student with the highest score and lowest score respectively.

C.

Allow fifteen​ students, chosen at​ random, an extra day to study for the microeconomics test. Then measure the test score differences between students who got the extra day to study and those that did not.

D.

All of the above could be ideal randomized controlled experiments.

Consider the following randomized controlled​ experiment:

You allow fifteen​ students, chosen at​ random, an extra day to study for the microeconomics​ test, and then measure the score differences between those who got the extra day to study and those that did not.

Which of the following could be impediments to implementing this experiment in​ practice?

A.

It could be costly to administer the same test to two different groups of students in the same class on different days.

B.

It could be considered unethical to allow some students more time to study.

C.

It could be against school policy to administer the same test to two different groups of students in the same class on different days.

D.

A and C only.

E.

All of the above could be impediments to implementing this experiment in practice.

Answer 1

Q.1) Suppose that you want to measure the causal effect of hours spent studying on the performance on a microeconomics test for a class of 30 students. Which of the following could be an ideal randomized controlled experiment to study the desired causal​ effect?

Correct Answer:

C. Allow fifteen​ students, chosen at​ random, an extra day to study for the microeconomics test. Then measure the test score differences between students who got the extra day to study and those that did not.

Explanation:

For an ideal randomized controlled experiment, the test group should be chosen at random. The test group should be given the extra time, while the control group shouldn't.

The selection should be completely random, and not on the basis of previous grades. All the students should not be part of the test group, ideally it should be about half.

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Q.2) Consider the following randomized controlled​ experiment:

You allow fifteen​ students, chosen at​ random, an extra day to study for the microeconomics​ test, and then measure the score differences between those who got the extra day to study and those that did not.

Which of the following could be impediments to implementing this experiment in​ practice?

Correct Answer:

C. It could be against school policy to administer the same test to two different groups of students in the same class on different days.

Explanation:

If the same test is administered to two different groups of students in the same class, on different days, there could be allegations that the question paper is no longer valid, or confidential.

While the researcher may be able to ignore the extra cost involved, it will be very difficult to ignore this bias. The test group obviously will have an advantage, and most educational institutes prohibit this.