The dependent variable in science is the variable that changes based on how the independent variable is changed. In general, the dependent variable is represented by the letter y and the independent variable is represented by the letter x.In a well-designed experiment, there is only one independent variable. Anything else that could affect how the dependent variable changes should be controlled.
. However, it an experiment, this is not always possible, so during data analysis, statistical analyses are used to help normalize for other factors that may have affected the independent variable. This normalization process helps show whether or not any correlation between the dependent and independent variable really resulted from the changes in dependent variable.One example of an experiment with a dependent and independent variable is an experiment that looks at the effect of wavelength of light on plant growth. In this case, the independent variable is the wavelength of the light (which corresponds to color: green, red, blue, yellow, etc). This is the variable that is manipulated and it does not depend on anything other than the will of the experimenter. Plant growth is the dependent variable. How many inches the plant grows, theoretically, depends on the color of the light. At the end of the experimental time, it is possible to plot the results to see how many inches the plants grew in each respective wavelength. If the line is completely flat, then there is no effect on light color and plant growth. If there is a slope to the line it shows some correlation between wavelength and the plant's growth.Remember that the correlation between the two does not show causation. A careless experimenter may have watered the plants differently, placed the plants in different conditions, temperature may have been different etc. If the experimenter does not control for these variables as well, then a correlation will not show causation, but rather the carelessness of the experimental methods used. For more information, please see: http://www.reference.com/motif/Science/controlled+variable
