Psyc 210 HOMEWORK 03

Psyc 210 HOMEWORK 03 - b Sketch the distributions involved...

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Psyc 210: Statistical Principles in Psychological Research HOMEWORK 3 DUE: FEBRUARY 18-21 Please show all of your work on a separate sheet. 1. On a particular memory task in which words are learned in random order, it is known that people can recall a mean of 11 words with a standard deviation of 4, and the distribution follows a normal curve. A cognitive psychologist, to test a particular theory, modifies that task so that the words are presented in a way in which words that have a related meaning are presented together. The cognitive psychologist predicts that under these conditions, people will recall so may more words that there will be a large effect size. She plans to test this with a sample of 20 people, using the .01 significance level, two-tailed. a) What is the power of this study?
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Unformatted text preview: b) Sketch the distributions involved, showing the area for alpha, beta, and power. c) How large would her sample size need to be in order to achieve a power level of .8? 2. In a planned study involving a standard test, the population is known to have a mean of 500 and a standard deviation of 100. The researchers predict that their planned experimental procedure will produce a large effect. What is the predicted mean of the population that will be given the experimental procedure? 3.In a completed study, there is a known population with a normal distribution, µ = 25 and σ =12. What is the estimated effect size if a sample given an experimental procedure has a mean of (a) 19, (b) 22, (c) 35? Also indicate whether the effect is approximately small, medium, or large....
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This note was uploaded on 04/26/2008 for the course PSYC 210 taught by Professor Chow during the Spring '08 term at UNC.

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