16 Questions
What is the effect size in the population relevant for the study?
0.5
In a power analysis, what does the significance level α of 5% indicate?
The probability of making a Type I error
Why does the sample size need to be doubled if values in the table refer to one group?
To account for two-tailed hypothesis testing
What does a power level of 80% signify in a power analysis?
The probability of detecting a true effect
Which factor directly influences the required sample size in a power analysis?
Difference in blood pressure before and after intervention
What is the purpose of using G*Power or similar software in sample size determination?
To calculate statistical power and determine required sample sizes
What is the purpose of conducting a power analysis before a study?
To determine the required sample size to detect a specified effect size
In the context of the given example, what does the effect size of 0.5 represent?
The expected difference in blood pressure between the treatment and control groups
What is the allocation ratio in the given example?
1:1
What is the total sample size required for the study based on the power analysis?
128
Which of the following is NOT a required input for the power analysis in the given example?
Standard deviation of the outcome variable
What is the purpose of conducting a power analysis in the given research study?
To determine the minimum sample size required to detect a clinically important difference between the treatment groups
What is the effect size (d) based on the given information?
0.5
In a randomized controlled trial, what is the purpose of having a control group?
To serve as a baseline for comparison with the treatment group
What is the significance level (α) chosen for the statistical analysis in this study?
0.05
If the standard deviation of blood pressure in the population changes from 20 mmHg to 15 mmHg, how would the effect size (d) be affected?
The effect size would increase
Learn how to calculate the sample size needed for a two-sample t test using statistical software R. The quiz covers determining the sample size before the study and allocation ratio, with an example calculation provided using R code.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
