3. Biostatistics

Study Power — Quiz

Test your understanding of study power with 5 practice questions.

Practice Questions

Question 1

In the context of power calculations, what is the relationship between the standard deviation of the outcome variable and the required sample size?

Question 2

A public health researcher is designing a study to compare the effectiveness of two different health education programs on reducing smoking rates. They initially plan for a significance level ($\alpha$) of $0.05$ and a desired power of $0.80$. If they decide to increase the desired power to $0.90$ while keeping the significance level and effect size constant, what is the expected impact on the required sample size?

Question 3

Which of the following scenarios would necessitate the largest sample size to achieve adequate statistical power in a public health study?

Question 4

In a public health study, what is the primary consequence of setting the significance level ($\alpha$) too high (e.g., $0.10$ instead of $0.05$) without adjusting other parameters in a power calculation?

Question 5

A public health researcher is planning a study to assess the impact of a new policy on childhood vaccination rates. They are particularly interested in detecting a 'minimal clinically important difference' (MCID) of $5\%$ increase in vaccination coverage. If they determine that a sample size of $N=500$ is required to achieve $80\%$ power with this MCID, what would be the likely impact on the required sample size if they instead wanted to detect an MCID of $2\%$ (a smaller difference) with the same power?