Psychology 2810 Lecture Notes - Lecture 10: Statistical Hypothesis Testing, Type I And Type Ii Errors, Decision Rule
10 Apr 2018
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When the population standard deviation ( x) is known and/or when n 30. Measure all participants on a single variable of interest. Calculate mean scores of all participants in sample on variable of interest. Compare sample mean against a meaningful typical average (z-test) First step is to make sure the problem qualifies for using a z-test. This is in relation to a population mean not a sample mean. We use samples represented a population (not sample data which we"re using) because that"s our end goal -- to represent population. Critical value sits at the boundary of rejection/non rejection region. The critical value allows us to determine at what point we reject or accept the test. When we don"t know the population standard deviation but the sample size > 30 then we can just use the sample standard deviation in its place. Always be sure to include a therefore statement. Use normal curve tables to find zobt (critical value)
