Many studies have shown that women who smoke while pregnant tend to have babies who weigh significantly less at birth, on average, than women who do not smoke while pregnant.
a. Identify the population(s) of interest in these studies.
b. Identify the explanatory variable in these studies. Also classify this variable as categorical or quantitative.
c. Identify the response variable in these studies. Also classify this variable as categorical or quantitative.
d. Socioeconomic status is potentially a confounding variable in these studies. Explain what it means for this to be a confounding variable in this context, and describe how this could provide an alternative explanation to concluding that smoking while pregnant causes lower birth weight in babies.