PSYC 251 Lecture Notes - Lecture 2: Type I And Type Ii Errors, Null Hypothesis
Document Summary
A proposed explanation for a phenomenon that makes testable predictions. You can prove a theory to be false, but you never prove a theory to be true. The default position, stating that there is no relation, no phenomena, and/or no effect to study. In proving the null hypothesis wrong you gather evidence for your alternative hypothesis. Type ii error is when you miss an effect but your statistic comes our nonsignificant. Don"t get to set beta, determined the effects of what you are studying. Working example: do younger people have better memory. Null hypothesis: young and old remember the same number of words. Our hypothesis: young and old remember different number of words. Can manipulate power but you can"t set it to be an exact number. Power occurs when a score falls past the alpha threshold. Would make you reject the null hypothesis. Null hypothesis is that the conditions you"re comparing aren"t different.
