PSY201 9.30.13 To Post

PSY201 9.30.13 To Post

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Unformatted text preview: Shaded region is power Opposite shaded region is beta β Shaded region is alpha PopulaDon 1 PopulaDon 2 Z =  ­1.645 Shaded region is power Opposite shaded region is beta β Shaded region is alpha PopulaDon 1 PopulaDon 2 Z =  ­1.645 2. [email protected] standard [email protected]   The smaller the populaDon standard deviaDon, the more power you have.   This is due to less overlap between the distribuDons (again, easier to find an effect) 15 9/29/13 Shaded region is power Opposite shaded region is beta β Shaded region is alpha PopulaDon 1 PopulaDon 2 Z =  ­1.645 Shaded region is power Opposite shaded region is beta β Shaded region is alpha PopulaDon 1 PopulaDon 2 Z =  ­1.645 3. Sample size   The larger the sample size, the more power you have.   Larger sample size leads to smaller SD of the distribuDon of means, which leads to: ▪  Less overlap between the distribuDons 16 9/29/13 4. Significance level   The more stringent the significance level (for example, p < .05 vs. p < .01), the less power you have.   More stringent p ­value, the more extreme the cut ­ off score Shaded region is power Opposite shaded region is beta β Shaded region is alpha PopulaDon 1 PopulaDon 2 Z =  ­1.645 Shaded region is power Opposite shaded region is beta β Shaded region is alpha PopulaDon 1 PopulaDon 2 Z =  ­2.33 Z =  ­1.645 17 9/29/13 5. One ­tailed vs. Two ­tailed tests   One ­tailed tests have more power than two ­tailed tests.   With a one ­tailed test, there is a less extreme cut ­ off scores on the distribuDon: ▪  More area in the power region 1.  2.  3.  4.  5.  Effect size Standard deviaDon Sample size Significance level One ­ vs Two ­tailed 18...
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This note was uploaded on 03/24/2014 for the course PSY 21201 taught by Professor Bernard during the Winter '13 term at SUNY Stony Brook.

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