Studies have shown that children in the U.S. who have been spanked have a significantly lower IQ score on average than children who have not been spanked.
a. Is it legitimate to conclude from this study that spanking a child causes a lower IQ score? Explain why or why not.
b. Explain why conducting a randomized experiment to investigate this issue (of whether spanking causes lower IQs) would be possible in principle but ethically objectionable.