aims, hypotheses and variables

• An aim is a statement outlining the purpose of the investigation.
• An aim must relate to the research question.
• If there is more than one aim, they must be related.
• An aim must be one sentence.
• An aim must be clear.
• A research hypothesis is a testable prediction of the relationship between two or more variables that shows the researcher's expectations of the results.
• A research hypothesis is formulated before the investigation begins.
• A research hypothesis provides a focus for the investigation.
• A research hypothesis can be supported or refuted.
• A research hypothesis must be one sentence.
• A research hypothesis refers to events/characteristics that can be observed or measured.
• A research hypothesis is based on observations, theory, a model or research findings.
• Drivers who have mobile phone conversations while driving will perform a greater number of driving errors than those who do not have mobile phone conversations while driving.

  Research hypothesis
• To examine the effects of different types of feedback on performance of a novel task.

  Aim
• A theory is a general explanation of a set of observations about behaviour and/or mental processes that seem to be related.
• A model focuses on representing how some behaviour and/or mental processes occur. It is often presented in the form of a diagram with boxes and arrows to show relationships between different concepts.
• A controlled experiment is an experimental investigation to test the relationship between an independent variable and a dependent variable, while controlling all the other variables.
• A variable is something that can change or vary in amount or type and is measurable.
• Examples of variables


  Age, gender, memory, exercise
• What role does the independent variable play in a cause and effect relationship?

  cause
• The independent variable has two values in a simple experiment.
• In an experiment on whether watching a violent TV program increases aggressive behaviour, the independent variable will be…

  Exposure or non-exposure to violence in a TV program
• What role does the dependent variable play in a cause and effect relationship?

  possible effect
• The dependent variable is sometimes referred to as the measurement variable, as it provides a measure of the participants' response to the independent variable.
• The dependent variable usually has a numerical (quantitative) value.
• The dependent variable is the variable that is used to observe and measure the effects of the independent variable.
• An extraneous variable is a variable other than the independent variable that may have an unwanted effect on the dependent variable and the results.
• An extraneous variable makes it difficult to conclude if the independent variable made the change in the dependent variable/results or if another variable has.
• It is best to identify extraneous variables prior to the research being conducted.
• Researchers focus on controlling variables that will have a significant effect on the dependent variable and results.
• Name three extraneous variables on an experiment testing the effect of caffeine on exam performance.

  Time of day, amount of sleep, amount of time spent studying
• A controlled variable is a variable that is considered to have an effect on the dependent variable so it needs to be held constant (‘controlled’) to remove its potential effects.
• The independent variable is the variable that is manipulated in order to measure its effect on the dependent variable.
• Three key parts of a research hypothesis include the independent variable & dependent variable being investigated, the strength/direction of the dependent variable (whether it is going to decrease, increase, etc.) and the comparison of groups being investigated.