Quantitative Research Methods - Hypothesis tests and T testes

Inferential Statistics

• Prevent unreasonable conclusions from data
• Use samples to infer about populations
• Calculate probability that the effects in the data could have arisen by chance
• Alow a decision if chance or 'real effect'
• 'Real effects' have below threshold probability of arising by chance
• Significance threshold in Psychology usually at a=0.05 or 0.01 for larger studies

Several tests can be employed for data analysis, best test depends on research question and type of data:

• For nominal data - binormial or chi-square tests
• For continuous data the test depends on the research question: relationships between variables - correlation; diffrences between groups - t test or similar
• Parametric methods for normally distrubuted data
• Non-parametric methods for non-normal data

Parametric vs Non-Parametric Tests

Parametric statistics, such as the t-test assume, that:

• The data we have collected are normally distrubuted. If that is not the case, or we have reason to believe it is not the case, we should use non-parametric tests
• If…