Don't need a lot of manpower. If you follow the procedure, it includes the questionnaire design in the early stage, the training of investigators, salary, questionnaire collection, data analysis and the final questionnaire report. If a professional investigation company is hired, the expenses will be within 500 yuan.
This is mainly a data processing and investigation report formation. If you just want to investigate related things yourself, as long as the questionnaire design is scientific and the price is not expensive, you can investigate and analyze it yourself.