A mixed method research includes (i) hypothesis or quantitative research questions (ii) qualitative research questions, and (iii) mixed method research questions. As you know, previous sections have been dedicated to explaining how hypothesis or quantitative and qualitative research questions should be written and what their characteristics are. 

While planning mixed method research studies, research questions should be written in a way that transcends quantitative and qualitative methods and requires use of mixed method. In other words, mixed method research questions should not emphasize only quantitative or qualitative research approaches but they should combine both methods. Writing research questions in this way is also known as method centered approach. However, writing research questions in this way entails a certain command of knowledge about mixed method designs. Accordingly, a researcher should develop her/his research questions compatible with the research design s/he will employ.

The second approach to writing mixed method research questions is labeled as content-centered approach.