Final answer:
To increase the power of their analysis, researchers could examine more groups, such as 15 instead of 10, which would increase sample size, or select specific groups to reduce variability. However, increasing the rate of random error or the length of survey questions are not effective strategies for increasing power.
Step-by-step explanation:
In the statistical analysis of the effectiveness of CHW intervention, where researchers calculated the average percentage of postnatal care use found in 10 randomly selected groups of 50 mothers, various methods could be employed to increase the power of their analysis. Increasing the power of a study generally leads to a better chance of detecting a true effect if one exists, reduces the risk of Type II errors, and ultimately enhances the validity of the research findings.
To increase the power of their analysis, researchers could:
- Examine more groups - By examining 15 randomly selected groups instead of 10, they increase the sample size, which can lead to a more precise estimate of the population parameter and therefore increase the statistical power.
- Select specific groups - Selecting groups comprised of CHW using mothers only would potentially control for variability and thus enhance the power, but it may also reduce the generalizability of the results, depending on the research question.
- Increasing the rate of random error is not a method to increase power. In fact, reducing random error (increasing precision) and controlling for confounding variables are traditional strategies to enhance power.
Option 2, which suggests increasing the length of survey questions, is not typically a strategy used to increase the power of an analysis as it does not directly impact sample size, variability, or the effect size.