CHAPTER3_Worksheet

An independent variable is the one thing you intend to vary/change in an experiment. A dependent variable is the thing that will change that you intend to measure as a quantitative assessment of the effect. A confounding variable is a variable that: 1. Affects the response variable and also 2. is related to the explanatory variable. A potential confounding variable not measured in the study is called a lurking variable. Usual Experimental Hypotheses/Statement If I _________(Independent Variable)______ then __________ (Prediction about your dependent variable)____________ because _____(Why, based on your research did you make this prediction?)__________________. In the following examples identify the independent and dependent variables and then also list several poten- tial confounding variables that the experimenters would have to consider. Sample Hypotheses/Experiments 1. If I increase the exposure to ultraviolet light, then people will have a higher frequency of skin cancer because ultraviolet light causes cells to become cancerous. Independent variable – Dependent variable – Confounding variables- 2. If I lower the temperature of the room the plants are in, then the leaves will change color because the leaves change color in the fall. Independent variable – Dependent variable – Confounding variables- 3. If I soak seeds in water before planting, then the seeds will germinate faster because the baby plant will not have to open a hard seed before growing. Independent variable – Dependent variable – Confounding variables- 4. If my dog pet is fed more , then my dog will gain weight because he is eating more calo- ries . Independent variable – Dependent variable – Confounding variables-