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Computing Statistical Power Online
Because manual computation is complex, researchers typically compute the statistical power for various research designs using online tools and downloadable programs, such as Russ Lenth’s Power and Sample Size Page or G*Power. By inputting the expected relationship strength, the sample size, and the level, these applications calculate the study's power or determine the exact sample size required to achieve a desired power level, such as .
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Research Methods in Psychology - 4th American Edition @ KPU
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Power analysis and effect size in mixed effects models: A tutorial
Type II Error
Increasing Statistical Power
Computing Statistical Power Online
Relationship Between Statistical Power and Type II Error
Adequate Statistical Power
Relationship Between Statistical Power and Relationship Strength
Which of the following best defines the statistical power of a research design?
A researcher designs a study with a statistical power of .80. This means there is a 20% probability that the study will fail to detect a real effect that actually exists in the population.
A researcher is refining their study design to improve the probability of detecting a real relationship between variables. Match each design decision with its specific impact on the study's statistical power.
A researcher is designing a study to examine how social media use affects attention span. Arrange these four study configurations in order from the lowest statistical power (at the top) to the highest statistical power (at the bottom) by analyzing how their parameters influence the probability of detecting a real relationship.
A researcher is developing a study to detect a subtle relationship between sleep duration and cognitive performance (). With a fixed budget that limits the sample size to participants, which of the following research plans correctly synthesizes the necessary design elements to maximize statistical power?
Example of Sample Size Requirements for High Statistical Power
Assuming a real effect exists in the population, arrange the following study designs in order based on their probability of failing to detect that effect (Type II error), from the highest risk of error (at the top) to the lowest risk of error (at the bottom).
A researcher is evaluating two proposed study designs for a clinical trial. Design A has a reported statistical power of , while Design B is estimated to have a probability of failing to detect a real effect that exists in the population. To ensure the highest probability of correctly identifying a relationship, the researcher should select the design with a power of _____.
Match each term related to statistical power with its correct description.
Learn After
A researcher is using an online application such as G*Power or Russ Lenth’s Power and Sample Size Page to determine the sample size required for a new study. Which of the following best describes how these tools function to provide this information?
A researcher is planning a study on how social media use affects attention span. Arrange the steps they would take to use an online power-analysis tool to determine the necessary sample size.
A psychology researcher is using an online application (such as G*Power) to evaluate their study design. Match each research design change with the specific calculation update the tool will provide in response.
True or False: A researcher who uses an online application such as G*Power to evaluate their study design and finds a power level of should judge the design as being methodologically insufficient based on the common scientific goal of achieving a power level of at least .
A researcher is developing a study on the relationship between sleep hygiene and cognitive performance. To ensure the study is methodologically sound, they must use an online power-analysis tool (such as G*Power or Russ Lenth's Power and Sample Size Page) to formulate their required sample size (). Which of the following plans best constructs the necessary set of parameters for this calculation to meet standard scientific goals?
True or False: To calculate a study's statistical power using online tools like G*Power, researchers only need to input the sample size and the level, as the expected relationship strength is automatically calculated by the software.
A psychology researcher is using an online power-analysis tool (such as G*Power) to design a new study. Match each parameter or output of the calculation with its specific role in the application.
When using online power-analysis tools such as G*Power, researchers typically aim to achieve a statistical power level of at least _____.
A researcher enters a small expected effect size, a sample of 40 participants, and α = .05 into G*Power and receives a power estimate of .58. Because she cannot change her effect size estimate or her α level, she must _____ her sample size in order to reach the conventional power target of .80.
A researcher has entered her study parameters into G*Power and received a statistical power estimate of .65. She must now evaluate whether this design is acceptable and, if not, determine the most defensible revision. Arrange the following steps in the order that best represents a sound methodological evaluation process.
Manual computation of statistical power can be highly complex. According to the course text, what are the names of the two software tools or downloadable programs that researchers typically use to compute power? Additionally, list the three parameters that must be input into these applications to calculate power or sample size, and state the standard level typically desired for statistical power.
Explain how Dr. Aris would use G*Power to determine his required sample size. In your explanation, identify what specific target power level he should aim for and how the program uses his inputs to calculate the sample size.
A researcher wants to use Russ Lenth's Power and Sample Size Page to find the sample size needed to achieve a statistical power of . If she sets her level to and expects a strong relationship strength, how should she enter these parameters into the application to calculate the sample size?