Psy 550 Final
• 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.
... [Show More] 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
Your Answer:
1. Type I error is made when we reject the null hypothesis, but the null hypothesis is actually true. Our decision is that the population means are not equal when they actually are equal- rejecting something that is true.
2. This would be a valid choice as Dr. R is rejecting a hypothesis that is false.
3. A Type II error occurs when the null hypothesis is accepted although in the population the research hypothesis is true. The population means are not equal, but the results of the experiment do not lead to a decision to reject the null hypothesis – failing to reject something that is false
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Explain the value of reversal designs (ABA designs) in single-case research.
Your Answer:
According to Privitera (2020), reversal designs are usually conducted in applied areas of research in order to investigate solutions that can be beneficial to either individuals or our society. One advantage is that the design can be used to apply treatments that benefit participants. In a reversal design (ABA design), a single participant is observed prior to (A), during (B), and after (A) a manipulation or treatment (p. 257-258)
A (baseline phase) --> B (treatment phase) --> A (baseline phase)
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Explain how a one-way analysis of variance works. How do you use between- and within-group variability?
Your Answer:
One-way analysis of variance (one-way ANOVA) looks at the differences between the mean of 2 or more samples. Between-group variability looks at the variations caused by differences between different groups. Within-groups variability looks at variations caused by differences within each individual group, differences not caused by the independent variable.
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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? B) Diagram it out. C) Assuming 20 subjects are needed per cell, how many subjects are needed for this study?
Your Answer:
a) The type of design would be a 2x2 factorial design as it will test the factors within one sample.
b) [Show Less]