I’d love to hear how you feel about my rationale for not teaching students how to evaluate studies based on internal validity. There is one exception, however: their IA. I only introduce the concept of internal validity during the analysis of their IA results and procedures, as this is the only study I expect them to be able to make …
What are the design types in experiments?
Choosing the best research design for your experiment is an important part of the planning process. When conducting an experiment for the IB Psychology IA, you must think very carefully about which design is best for your purposes. Experimental Designs (MP, IS, RM) There are three design types of experiments: Independent Samples Repeated Measures Matched Pairs Independent Samples is when the …
What is a “controlled variable?”
A controlled variable is a variable that’s kept constant between the conditions of the experiment so that the only difference between the groups is the independent variable. Imagine you’re doing an experiment on yourself to see if drinking coffee in the morning gives you energy. On Monday you wake up, do yoga and then have a cup of coffee. At …
Operational DefinitionsHow to operationally define IVs and DVs
Updated May 2020 Operational definitions became important in Psychology when psychologists wanted to establish that psychological experimentation is truly scientific in nature. In this blog post, we’ll look at exactly what is an operational definition is and how to do it. This is a common error in IB Psychology IAs. Hopefully after reading this post, students will be able to …
Hypotheses
Updated June 2020 Writing good hypotheses in IB Psychology IAs is something many students find challenging. After moderating another 175+ IA’s this year I could see some common errors students were making. This post hopes to give a clear explanation with examples to help with this tricky task. Null and Alternative Hypotheses Null Hypothesis (H0) The term “null” means having …