PSYC1001 Lecture Notes - Lecture 14: Observation, Null Hypothesis, Statistical Power
16 Aug 2018
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Document Summary
P-values vary between 0 and 1 and express a probability. However the critical cut- off p-value is typically p=0. 05. In psychology if the p-value is less than 0. 05 we would normally reject the null hypothesis. If the p-value is greater than 0. 05 we would normally retain the null hypothesis. Statistical power can be defined as the probability of correctly rejecting a null hypothesis when it is false probability of finding an effect when there is an effect to be found. Accepting the null hypothesis means to accept it based on evidence that you have found to support it. Whereas retaining it occurs if you cannot find evidence inconsistent with the null hypothesis we can"t necessarily disprove what is going on. The difference between retention and acceptance is that by retaining a null hypothesis, you are not placing full loyalty on it. Observational bias is the tendency to see what we expect to see, or what we.
