Unit 2 Research and Methods

Module 6 – Do First Do First: The image to the right (and on your papers) is the plot of a correlational study. How would you describe the relationship between the X and Y variables? Done early? If you DID the homework, please move to the front – if you did not, please move to the back so that you may complete it in peace.

Module 6 – Correlation and Experimentation

Module 6 Objectives SWBAT: differentiate the types of research, including correlational and experimental research SWBAT: describe a correlational study SWBAT: describe an experimental study

Correlation Correlation How often do A and B occur together? Correlation co-efficient: Number that details how strong or weak a relationship A and B have Ranges from -1.00 to +1.00 Positive correlation = when A increases, B increases Stronger the correlation, higher the NUMBER Negative correlation = when A increases, B decreases, and vice versa Scatterplots: Pretty clearly show trends in data

Correlations Practice With your tablemates, practice the correlational work on your classwork papers. For Part I, determine which of the pairs of numbers is the STRONGEST correlation. For Part II, give examples of positive correlations you’ve seen before. For Part III, give examples of NEGATIVE correlations you’ve seen before.

Does correlation = causation? Consider the following correlation: In studies, it’s been determined that people with low self-esteem often also have depression. What could you say about the relationship between low self-esteem and depression?

Does correlation = causation? Let’s get a better example. How would YOU (and your table) best explain the data on the graph to the right? Another example. What kind of confounding or unknown variable could cause this relationship?

Does correlation = causation? So sometimes correlations are caused by a third factor, but other times… What does the image below seem to tell us? KEY POINT QUESTION: Do correlations show us cause and effect? Why or why not?

Experimentation – The BEST Way! An attempt to isolate cause and effect Characterized by a control of variables: Independent variable – the variable being manipulated Dependent variable – the variable that the IV changes Experiments are characterized by EXPERIMENTAL groups (groups that you apply the treatment or change to) and CONTROL groups (where the researcher does nothing) Why is it important to have control groups?

The Power of Random Random assignment: Why did the experimenters in this clip use a coin to place people into the two groups? What would have been the impact if they DIDN’T randomly assign people in their experiment? Confounding variables: A variable that unintentionally influences the outcome of the experiment So – you want to control for AS MANY THINGS as possible EX: In a study on a pain medication, the experimental group was pre-dominantly redheaded, while the control group was heavily mixed. Ultimately, much more medication than expected was needed for the experimental group to reduce their pain. What possibly interfered? Random assignment handout

Practice! Identify the following in each scenario with your group: IV, DV, control group, and if available, confounding variable