# PSY unit 2 discussion 2 CAUSE AND EFFECT

### Cause and Effect

In our daily lives, we often conduct little experiments to detect cause-and-effect connections. If you are interested in gardening, for example, you might try adding plant food to one bed of flowers but not another and then ask the question: Does the use of plant food (the independent variable) affect the size of the flowers (the dependent variable)? By comparing unfed plants (the control group) to those receiving plant food (the experimental group), you could then find out whether plant food is worth using.

For this discussion, you will apply research terms to a sample informal experiment, and you will think of an informal experiment of your own that you have either tried or might like to try. Please note that you are not required to conduct the experiment. The goal is to apply the terms to your idea for an experiment.

#### Part 1

Select an informal experiment from A or B below:

• A: Karl wants to determine whether adding a gas treatment to his full gas tank really does help increase the number of miles to the gallon his car gets. He suspects it does help but wants to test it to be sure he is getting his money’s worth for the treatment. He decides that for one month, he will track his gas mileage without the treatment. He records his gas mileage for the month. The next month, he adds the treatment each time he fills his tank. He records his gas mileage for the month and compares the mileage of the two months.
• B: Carolyn is frustrated that getting her third-grader son, Jacob, to complete his homework after school results in a daily argument. She wants to find a strategy that will reduce the struggle. She has always allowed him to watch TV or play for an hour before beginning his homework. She thinks that maybe having him complete the work before watching TV or playing will have better results. She decides to alternate the schedule for one month. During Weeks 1 and 3, she has Jacob complete his homework before playing and records the amount of time it takes him to get started on his homework. During Weeks 2 and 4, she switches to the former routine of allowing an hour of play time before beginning homework. She records the amount of time it takes him to get started on his homework. She compares the total times for the two approaches.

For the informal experiment you selected from above, in full sentences describe each of the following:

• Hypothesis.
• Independent variable.
• Dependent variable.
• Possible extraneous variable.

#### Part 2

Think of an experiment you have conducted or might like to conduct. Describe your informal experiment, and then in full sentences describe each of the following:

• Hypothesis.
• Independent variable.
• Dependent variable.
• Possible extraneous variable.