Aims and hypotheses

• An aim is a clear general statement made about what the investigator intends to research. This may include the purpose of the study (eg following on from findings of a previous study to develop a theory or replicate).
• A hypothesis is a testable statement including levels of the independent and dependent variables (or both covariables for a correlation study).
• Operationalisation is when variables are stated clearly, demonstrating how they are measured (eg the DV is the NUMBER of words recalled, not just 'recall'). The IV must also be clearly state both levels (eg participants recalling in green light and participants recalling in blue light).
• Null hypothesis states there is no change / difference in the measurement of the DV as a result of manipulation of the IV.
• Alternative hypothesis states there is a change / difference in the measurement of DV as a result of the manipulation of the IV.
• Hypothesis testing is when data is collected and statistical testing is conducted on the data. This provides evidence for the null to be rejected and the alternative to be accepted.
• Non-directional (two tailed) states that there is a difference in the measurement of DV as a result of the manipulation of the IV, but does not state the direction the results will go (eg there is a difference in the number of words recalled in green light compared to participants recalling in blue lights)
• Directional (one tailed) hypothesis state there is a difference in the measurement of the DV as a result of manipulation of the IV and states the direction of the results (eg there is an increase in the number of words recalled in green light compared to blue light).
• Researchers only use a directional hypothesis if there is previous research that suggests which way the results are likely to go.
• Falsifiability:

  • Any theory, even though backed up with a significant amount of evidence, should be open to the possibility that new research that emerges will contradict its basic principles. The more a theory is to withstand attempts to falsify, the more confidence it provides in the conclusions.