PSYC 2021 Lecture Notes - Type I And Type Ii Errors
22 Dec 2013
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Hypothesis test: in stats, we ask questions. One sample mean test it is rarely done. You usually compare groups with it: for example: after 9/11 or earthquake in japan, find population scores of happiness/stress levels. You can"t study what happens before and after, so use theoretical values. Theoretical values for (population mean) and s (sample standard deviation): draw sample and deliver treatment. There are 2 possibilities: 1) the mean after treatment is smaller because the therapy works. 2) by sampling error, i selected happy rats: sampling distribution. Outcome is unlikely under scenario that therapy didn"t work (region near tail end of distribution) Decision line usually appears at the last 5% in the tail end of the distribution. H1 (alternative hypothesis): therapy works: 2 conclusions: 2) fail to reject null (therapy didn"t work: h0: =28. 7, h1: <28. 7, 28. 7. Step 1: state hypotheses: h0: =28. 7, h1: 28. 7.
