PSY 350 Lecture Notes - Lecture 28: Effect Size, Standard Deviation, Test Statistic
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Factors that affect the likelihood of rejecting ho. If we"re comparing a sample mean to a population mean, our test statistic is: This means there are three factors that tend to make our z scores bigger: having a larger difference between m and . We call this the effect size: having a smaller population standard deviation. This makes the standard error smaller: having a larger number of observations. H1: >0 h1: 1> 2 h1: r> 0. If we make a directional prediction, we"re only right if the effect goes in the direction we predicted. For example, if i predict that > 3. 5, and it"s actually significantly smaller than 3. 5, that"s not support for my hypothesis. On the other hand, it may not make sense to look for values at either end of the distribution of sample means if we"re only interested in one end. If we are only interested in one end.
