PSYC 218 Lecture Notes - Lecture 13: Repeated Measures Design, Effect Size, Sampling Distribution
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Z test: need to know population mean and population sd. In z and t tests for single sample experiments, we had to specify at least 1 parameter ( ) If we think we know , we may not know if it"s accurate. We"ve already seen one test for a two condition experiment (a sign test!) Now, we"re going to focus on t test for two condtions. Pairs of subjects matched on one or more characteristics serve in both conditions. Difference score (d) calculated for each subject (or pair) and then analyzed. Just like the sign test, but now we use both sign (direction) and size of difference scores. Analysis treats different scores as if they were the single, only, raw scores. You hypothesize that endorsing increased social spending affects politicians" popularity no direction. Then add a difference (d) category, with results such as -2 for top, etc etc. D (sum of diference score) = 22.
