Psych: Can you identify the independent variable(s) and the dependent variable(s) in each example?

Do children learn to read better when using the "whole word" (traditional method) or "phonics" method? 100 2nd grade children are divided into groups & taught using one method or the other. They take a battery of reading tests at the end of the school year

. 3) Independent Variable: Type of reading method; dependent variables: scores on reading tests.

A research psychologist was interested in the effects of TV violence on aggressive behavior in children. Ninety 9 yr. old children were randomly assigned to one of three conditions: a) watch one hour long violent TV program, b) watch one hour long nonviolent TV program, c) no TV watching. Then each child was permitted to play in a laboratory "playroom" that contained both nonagressive (blocks, stuffed animals, games) and aggressive (guns, arrows, swords, aggressive games) toys. Researchers recorded the amount of time each child spent playing with aggressive toys.

1) Independent Variable: Type of TV watching; Dependent Variable: Amount of time spent with aggressive toys.

An automobile manufacturer wants to know how bright brake lights should be in order to minimize the time required for the driver of a following car to realize that the car in front is stopping. Brakes of : 1) no light (0 watts), 2) low brightness (100 watts), 3) medium brightness (300 watts), and 4) maximum brightness (500 watts) are tested. The researchers test the effectiveness of the brake lights by recording the time it takes for a driver (in a simulator) to hit the brakes when brake lights appear in front of him/her.

2) independent variable: Brightness of the lights; Dependent variable: amount of time until stopping.