Final answer:
The questionnaire method allows for the collection of both quantitative and qualitative data on jobs.
Step-by-step explanation:
A major advantage of the questionnaire method of gathering data on jobs is that it allows for the collection of both quantitative and qualitative data. Closed-ended questions in the questionnaire can provide quantitative data, such as yes-or-no or multiple-choice responses, which can be counted and statistically analyzed. Open-ended questions in the questionnaire can provide qualitative data, such as short essay responses, which can give a wealth of material and insights into the participants' thoughts, experiences, and beliefs.