1.3 You are asked to study the causal effect of hours spent in remedial classes at schools by students who are struggling in mathematics on their final test scores and performance in the subject. Describe:

a. an ideal randomized controlled experiment to measure this causal effect;

b. an observational cross-sectional data set with which you could study this effect;

c. an observational time series data set for studying this effect; and

d. an observational panel data set for studying this effect.