Final answer:
The ranking of different analyses in evidence-based research based on decreasing bias is as follows: a) meta-analysis, randomized controlled trials, and observational studies, with meta-analyses being the least biased and observational studies the most.
Step-by-step explanation:
When ranking different analyses in evidence-based research on the basis of decreasing bias the correct order is: meta-analysis, randomized controlled trials (RCTs), and observational studies.
Here's why each is ranked as such:
- Meta-analysis is a technique that aggregates the results of many studies on a specific subject, providing a high level of evidence due to the large data set and the ability to detect patterns and averages across multiple studies.
- Randomized controlled trials are experiments where participants are randomly assigned to different groups, which helps to minimize selection bias and allows for a more direct cause-and-effect relationship to be determined between two variables.
- Observational studies, while important for gathering data, are more susceptible to bias because they involve documenting naturally occurring phenomena without manipulating variables.
In conclusion, the ranking from least to most bias is A) Meta-analysis, Randomized controlled trials, Observational studies.