PSY550 final exam - march 2018

Asked by bighero
Dated: 12th Jun'18 11:58 AM
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Q1 For each of the following examples, explain whether the researcher has made a correct decision or has made a Type 1 or Type 2 error. Explain why.
1.Dr. G rejects the null hypothesis although the independent variable had no effect.
2.Dr. R rejects the null hypothesis when it is false.
3.Although the independent variable had an effect, Dr. E does not reject the null hypothesis

2.Explain the value of reversal designs (ABA designs) in single-case research.

3.Explain how a one-way analysis of variance works. How do you use between- and within-group variability?

4. After watching nursery-school children, Ken Garoo wants to test the hypothesis that some toys are more fun to play with than others. He decides to compare “fun” toys (blocks) with “unfun” toys (stuffed animals). He also wishes to see if there is a sex difference, as well, so sex is added as an independent variable. A) What kind of design is needed? Diagram it out. C) Assuming 20 subjects are needed per cell, how many subjects are needed for this study?

5 Bill Board is “lording” his SAT score over his friend, Rhoda Dendron, who took the ACT. “You only got a 25 in math,” he chortled, “while I got a 300 in math.” Given that the SAT has a μ of 500 and a σ of 100, and the ACT has a μ of 20 and a σ of 5, what is wrong with Bill’s logic (give the answer in both z scores and percentile ranks).

6. Describe a two-matched groups design. How is the matching done?

Chuck Wagon is very excited about the within-subjects approach. “Now I’ll never need to run large numbers of subjects again,” he says. However, Chuck has forgotten that within-subjects designs may be a) useless, b) impossible, c) confounded by order effects, or d) impractical when excessive subject time spent in an experiment makes data inaccurate. Give an example of each of these four objections.

A researcher has studied subjects’ ability to learn to translate words into Morse code. He has experimented with two treatment conditions: in one condition, the subjects are given massed practice; they spend 8 full hours on the task. In the other condition, subjects are given distributed practice; they also spend 8 hours, but their practice is spread over four days, practicing 2 hours at a time. After the practice, all subjects are given a test message to encode; the dependent variable is the number of errors made. The researcher has matched the subjects on intelligence. The results are in the following table. Decide which statistical test would be appropriate, carry out the test, and evaluate the outcome. Assume a significance level of .05 and that the direction of the outcome has not been predicted.


Explain the pros and cons of longitudinal, cross-sectional, and sequential designs.


Define the term quasi-experiment and discuss the pros and cons of this research method.

PSY550 final exam - march 2018
Answered by bighero
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Dated: 12th Jun'18 11:58 AM
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Question-1.doc (25.5 KB)
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hypothesis     The   made by     is       null   is rejected     it       there   no error     in  
Question-2.doc (25.5 KB)
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that     controlled   in turn     possible       values   Gast, D     Ledford,       )   Single case     Applications       and   sciences
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time     the   In one     has       fact   samples are     the       population   be equal    
Question-4.doc (26.5 KB)
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5     2   giving the     of       10   Montgomery, D     Design       experiments   wiley sons    
Question-6.docx (16.32 KB)
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In     marching   typically done     precision       pair   the same     matching       are
Question_5.doc (23.5 KB)
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The     0   As such,     with       he   is low     to       has   25 with     being    
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5     and   p-value is     and       significance   we can     the       References   A G    
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trying     use   impractical excessive     cannot       and   variables (Keren,     Keren,       within-subjects   A methodological     Handbook      
Question_9.doc (26.5 KB)
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include     and   of possible     However,       include   and cohorts     and       regarding   consistency Sequential     main  
Question_10.doc (27 KB)
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causal     an   on its     without       this   account, quasi     allows       controlling