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Differentiating between directional and non-directional hypotheses. Non directional – also called two tailed. Experimenter predicts that two groups will be different; but doesn’t say in what direction Ho: μ 1 = μ 2 (null hypothesis) H1: μ 1 ≠ μ 2 (alternative hypothesis). Directional.
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Differentiating between directional and non-directional hypotheses
Non directional – also called two tailed • Experimenter predicts that two groups will be different; but doesn’t say in what direction • Ho: μ1 = μ2 (null hypothesis) • H1: μ1 ≠ μ2 (alternative hypothesis)
Directional • Experimenter predicts that one group will do better than the other (in this example E predicts that group 1 will be greater than group 2) • Ho: μ1 ≤ μ2 (null hypothesis) • H1: μ1 > μ2 (alternative hypothesis – this is the experimenter’s prediction)
Directional prediction • If E predicts that group 1 is less than group 2 then: • Ho: μ1 ≥ μ2 (null hypothesis) • H1: μ1 < μ2 (alternative hypothesis – this is the experimenter’s prediction)