Experimental and correlational research methods

Approaches in Psychology Research[ edit ] Nomothetic Quantitative Approach [ edit ] This approach is basically used in inferential and descriptive statistics as both mediums of scientific method of investigation in analyzing, presenting, and interpretation of data gathered by the researcher through standardized or objective instruments e. Psychologists who adopt this approach are mainly concerned with studying what we share with others. That is to say in establishing laws or generalisations.

Experimental and correlational research methods

Correlational Research Figure Each dot represents an individual. In correlational research we are interested in how two variables are related: How does change in one variable relate to change in another? Here, we do not intervene and change behaviour, as we do in experiments.

In correlational research we see patterns that go together, but we usually cannot infer what causes what. In addition, with correlational research you can examine only two variables at a time, no more and no less.

Consider the following example. The researchers asked people how much of their income they spend on others or donate to charity, and then asked them how happy they are.

As you might suspect, these two variables were related, but perhaps not in the way you predicted.

Research Variables

The more money people spent on others, the happier they were! To find out how well two variables go together, we can plot the relation between the two scores on what is known as a scatterplot. A scatterplot is a powerful data visualization tool. It uses X and Y coordinates to display the values of the two variables in our data set.

In Figureeach dot in the scatterplot represents a data point in this case it is individuals, but it could be some other unit. Importantly, each dot provides us with two pieces of information—in this case, information about how good the person rated the past month x-axis and how happy the person felt in the past month y-axis.

Which variable goes on which axis does not matter. According to Figurepeople are happier when they perceive the month is good as opposed to bad. The association between two variables can be represented using the scatterplot or summarized statistically using the correlation coefficient abbreviated asr.

A correlation coefficient tells us information about the direction and strength of the association between two variables.

For the example above, the direction of the association is positive. That means that people who perceived the past month as being good reported feeling happy, whereas people who perceived the month as being bad reported feeling less happy.

With a positive correlation, the two variables go up together and go down together. In a scatterplot, the dots form a pattern that extends from the bottom left to the upper right. The r value for a positive correlation is positive usually the positive sign is omitted.

Here, the r value is. Each dot represents a country. Chiao, A negative correlation is one in which the two variables move in opposite directions.

That is, as one variable goes up, the other one goes down. Figure shows the association between average height of males in a country and pathogen prevalence or commonness of disease of the country.

In this scatterplot, each dot represents a country. Notice how the dots extend from the top left to the bottom right. What does this mean in real world terms? It means that people are shorter in parts of the world where there is more disease.

Thervalue for a negative correlation is negative, that is, it has a minus — sign in front of it. Here it is —.

Experimental and correlational research methods

The strength of a correlation has to do with how well the two variables go together. The more people spent on others, the happier they were. At this point, you may be thinking to yourself, I know a very generous person who gave away lots of money to other people but is miserable!

Or maybe you know of a very stingy person who is happy as can be. Yes, there might be exceptions. If an association has a lot of exceptions, it is a weak correlation.40 Chapter 3 • Quantitative Versus Qualitative Research, or Both?

An example of this design is a study completed by Al-Kandari, Vidal, and Thomas () examining the relationship between a health promoting life-.

Psychology Research Methods in Psychology has been evaluated and recommended for 3 semester hours and may be transferred to over 2, Types of Research Methods Adapted from Edvantia SBR Rating for Technical Assistance Programs and Services form () and Carter McNamara Overview of Methods to Collect Information handout.

Correlation means association - more precisely it is a measure of the extent to which two variables are related. There are three possible results of a correlational study: a positive correlation, a negative correlation, and no correlation. Study Guides and Tips. There's a lot of information to absorb when it comes to studying psychology.

Correlation Coefficients

Learn about the fundamental theories, take sample quizzes, and master the inner workings of the mind. In general, experimental research is high in internal validity, correlational research is low in internal validity, and quasi-experimental research is in between. Exercises Discussion: For each of the following studies, decide which type of research design it is and explain why.

Case Study Research Design - How to conduct a Case Study