PSYCH 303 Lecture 8: Hypothesis Testing
16 Mar 2018
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Outline: between and within groups designs, experiments: confounds and internal validity, null effects, replications. Isolate variables of interest and control temporal ordering: requires random assignment of participants to conditions. Is there any other explanation: a study has internal validity when one has made sure that only the variables you are manipulating are responsible for the effect, that there are no other factors causing it. Threats to internal validity in experiments: observer bias is when the researcher"s expectations influence interpretations of results. Importance of sampling distributions: allows us to make inferences to the general population from samples we study. Instead of looking for confirmation, must look for disconfirmation of our hypothesis: null hypothesis: there is no difference, alternative hypothesis: there is a difference. In experiment, seek to deny the result that would occur if the null were true. What if the independent variable does not make a difference: not enough between-groups difference.
