Independent/ dependent variable notecards

A group of college students were given a short course in speed-reading. The instructor was curious if a monetary incentive would influence performance on a reading test taken at the end of the course. Half the students were offered $5 for obtaining a certain level of performance on the test, the other half were not offered money.

Independent variable: Monetary incentive ($5 or no money) Dependent variable: Performance on reading test

variable

an element, feature, or factor that is liable to vary or change

independent variable

a variable that is intentionally changed to observe its effect on the dependent variable

If a scientist conducts an experiment to test the theory that a vitamin could extend a person's life-expectancy, then the independent variable is the amount of vitamin that is given to the subjects within the experiment. This is controlled by the experimenting scientist.

independent variable: vitamin dependent variable: life span

A scientist studies the impact of a drug on cancer.

independent variable:administration of the drug. dependent variable:impact the drug has on cancer

You are interested in finding out which color, type, and smell of flowers are preferred by butterflies for pollination. You randomly choose an area you know to be inhabited by butterflies and note all the species of flowers in that area. You want to measure pollination of flowers by butterflies.

independent variable:flower color, type, and smell dependent variable:pollination by butterflies

dependent variable

the event studied and expected to change when the independent variable is changed

control

the variable that stays the same