Select the correct choices that complete the sentences. Confounding A designed experiment A lurking variable A confounding variable An observational study occurs when the effects of two or more explanatory variables are not separated. Therefore, any relation that may exist between an explanatory variable and the response variable may be due to some other variable not accounted for in the study. A designed experiment An observational study A lurking variable A confounding variable Confounding is an explanatory variable that was considered in a study whose effect cannot be distinguished from a second explanatory variable in the study. A lurking variable A designed experiment A confounding variable Confounding An observational study is where a researcher randomly assigns the individuals in a study to groups, intentionally manipulated the value of an explanatory variable, controls other explanatory variables at fixed values, and then records the value of the response variable for each individual. A designed experiment Confounding An observational study A lurking variable A confounding variable is an explanatory variable that was not considered in a study, but that affects the value of the response variable in the study. In addition, this variable is typically related to other explanatory variables in the study. Confounding A lurking variable A confounding variable An observational study A designed experiment involves the researcher measuring the value of