Hypothetical research question Are managerial leadership training classes effective for supervisors in reducing the high employee turnover rate? Hypothetical Research Design for Qualitative Research

Hypothetical research question

Are managerial leadership training classes effective for supervisors in reducing the high employee turnover rate? 

Hypothetical Research Design for Qualitative Research:Good leaders who completed leadership courses was able to lower the high turnover rate than the leaders who did not take any leadership courses.

Identify which specific inferential or analytic statistic(s) would be best to test the hypotheses and why?

You are being asked how you might compile and report the data hypothetically?

Please something simple and easy for me to understand. Thank you