PSYCH 241 Lecture Notes - Lecture 5: Null Hypothesis, Psych, Stroop Effect
18 Oct 2016
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Step 1: assume the groups do not differ (ho: assume the independent variable did not have an effect on dv, null hypothesis there is no difference. Step 2: compute appropriate statistic to test for group differences (e. g. , t-test: obtain the probability value for statistic (p value) Outcome has small likelihood of occurring under ho (p < . 05) Reject ho and conclude iv had an effect on dv. Difference between means is larger than what would be expected if error variation (change) caused the outcome. What do we conclude when a finding is not statistically significant: do not reject ho of no difference, do not accept the ho. Do not conclude that iv did not produce an effect: cannot draw a conclusion about the effect of iv. Some factor in experiment may have prevented us from observing an effect of the iv (2^0 variable?) The independent variable is manipulated between sets of different subjects one set for each level of iv.
