HOW SCIENCE WORKS IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS

IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Learning outcomes: By the end of the lesson you should be able to • Identify the two classifications of experimental research. • Explain what the different types of variables are. • Recognise different variables in example experiments. • Understand why the consideration of variables is important when designing an experiment.

EXPERIMENTAL RESEARCH • An experiment that involves the manipulation of one or more variables as well as the measurement of the effects of such manipulation or behavior.

CLASSIFICATION OF EXPERIMENTS TRUE EXPERIMENTAL QUASI - EXPERIMENTAL

TRUE EXPERIMENTAL RESEARCH an experiment that leads to an unambiguous outcome regarding what caused an event

QUASI-EXPERIMENTAL RESEARCH – semi | partial – it lacks some properties of a true experiment (randomization, control group, validity component)

IMPORTANT CHARACTERISTICS OF TRUE RESEARCH Some type of intervention or treatment is implemented.

IMPORTANT CHARACTERISTICS OF TRUE RESEARCH The experimenter has a high degree of control over the arrangement of experimental conditions, assignment of participants, systematic manipulation of independent variables and choice of dependent variables.

IMPORTANT CHARACTERISTICS OF TRUE RESEARCH Assign random participants in the experimental research (the most important characteristic)

IMPORTANT CHARACTERISTICS OF TRUE RESEARCH There is an appropriate comparison in order to evaluate the effectiveness of a treatment.

IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS The INDEPENDENT VARIABLE • Also known as the INPUT variable. • This is the thing that you change or manipulate, the thing you are testing.

IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS The DEPENDENT VARIABLE • Also known as the OUTPUT variable. • This is the thing that you measure or observe, it’s the results of the experiment. – You expect the dependent variable to be affected by the independent variable.

IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS The CONTROL VARIABLES • Any variable that you keep the same in order to allow for a ‘fair test’.

IDENTIFYING VARIABLES AND DESIGNING INVESTIGATIONS Example No. 1 • A student thinks that a 10 years old student will be better in doing a quiz than a 8 yrs old student. – Task 1: Write down the independent, dependent and control variables in this experiment.