Topic 4 DQ 1 An independent variable is one that stands alone. It will most likely influence the dependent variable. A dependent variable is what happens because of the independent variable. Extraneous variables are anything that could affect the research study (Flannelly 2014). For example, if the research topic was whether high concentrations of vehicle exhaust impact incidence of asthma in children, vehicle exhaust is the independent variable while asthma is the dependent variable (NIH 2017). The extraneous variable would then be any other different exposure that could also cause respiratory issues such as secondhand cigarette smoke or living or playing near factories (NIH 2017). One way the researcher could control an extraneous variable is to also put it into the research (NIH 2017). The sample they take of people need to all be exposed to the same factory or cigarette smoke (NIH 2017). Another way they could control the extraneous variable is to take it out all together and choose a sample from somewhere that has high incidence of car exhaust but no factories and none of the individuals participating exposed to secondhand smoke (NIH 2017). using 200-300 words APA format with at least two references to support this discussion Compare independent variables, dependent variables, and extraneous variables. Describe two ways that researchers attempt to control extraneous variables. Support your answer with peer-reviewed articles.