PSY201 9.30.13 To Post

645 shaded region is power opposite shaded region is

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Unformatted text preview: Z ­score [in the direcDon you care about!] a)  That percentage = power Power = 59.87% 0.58 0.74 0.9 1.06 1.22 .94 Shaded region is power Opposite shaded region is beta β Z = 0.25, Raw = 0.94 4.  Using the normal curve table, determine the probability (percentage) of geeng a score more extreme than that Z ­score [in the direcDon you care about!] a)  That percentage = power Power = 59.87% b)  Beta is the opposite of power (β = 100%  ­ Power) β = 100%  ­ 59.87% = 40.13% 0.58 0.74 0.9 1.06 1.22 .94 Shaded region is power Opposite shaded region is beta β Z = 0.25, Raw = 0.94 So what does this mean?? Power = 59.87% β = 40.13% Power is the probability that a study will produce a staDsDcally significant result if the research hypothesis is true. Our study design has about a 60% chance of finding a significant result. Beta is the probability that we will fail to reject the null hypothesis, when in reality the null hypothesis is false. Our study design has about a 40% chance of making a Type II error. 13 9/29/13 0.58 0.74 0.9 1.06 1.22 .94 Shaded region is power Opposite shaded region is beta β Z = 0.25, Raw = 0.94 Shaded region is alpha 0.88 1.04 1.2 1.36 1.52 Z =  ­1.645, Raw = 0.94 Power is influenced by: 1.  Effect size 2.  PopulaDon standard deviaDon 3.  Sample size 4.  Significance level 5.  One ­ vs. Two ­tailed tests 1. Effect size   The greater the predicted mean difference, the more power you have.   This is due to less overlap between the distribuDons (so easier to find an effect) 14 9/29/13...
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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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