probability and significance

• -          The 5% level of significance is regarded as being the minimum level of significance which is acceptable for regarding results as significant – because we are claiming that the difference between as set of scores is so large it is unlikely to have arisen due to chance – but cant be 100% as extraneous variables can affect our results
• -          P values are written as a proportion so – crocodiles e.g. p being equal too or les than 0.01 means there is a 1% probability the results occurred by chance
• -          P value represents the probability of something happening by chance and ranges from 0-1 with 0 representing no influence of chance and 1 representing a complete influence of chance
• -          Probability – we can never be 100% certain chance has not played a part in results and psychologist need to mathematically express the possibility that the results may have occurred due to chance
• -          But if the statistical tests show the change in the DV was due to the IV and not because of chance then we accept the experimental / alternative hypothesis
• -          If the changes in the dependant variable are due to chance then we accept the null hypothesis
• -          From statistical test researchers can draw conclusions and decide whether to accept or reject the null hypothesis and following this whether to accept or reject the alternative hypothesis
• -          Inferential statistics allow researchers to draw conclusions about their research because statistical tests tell them the likelihood that the results occurred by chance