a) Two variables are said to be confounded if one cannot separate their effects on a response variable. Give your own example of association where the presence of a lurking variable has a confounding effect. Specify clearly all the variables involved and the type of association. Explain the confounding effect. b) Give your own example of association where the presence of a lurking variable has a common response effect, i.e., there is association between the lurking variables and each of the two variables in the study. Specify clearly all the variables involved and the type of association. Explain the common response effect