What is distinguish between qualitative and quantitative data?

What is the difference between quantitative and qualitative analysis? Give several examples. Define quantitative analysis. What are some of the organizations that support the use of the scientific approach?

The following are reasons why randomized control trials (RCTs) are not used to investigate all research questions, except:    a. RCTs can be expensive, which can make it difficult if funding is limited   b. RCTs can be time-consuming, and it may take months and sometimes years to obtain final results   c. For certain research questions and/or certain types of exposure variables, it may not be ethical to conduct an RCT   d. RCTs are less valid than observational analytical study designs

If a researcher had an interest in medicine and wanted to learn more about the healthcare industry and profession by conducting qualitative interviews with professionals like a doctor or nurse as well as possibly interviewing medical students, what might be the researcher’s hypothesis, presumptions, or expectations?