As much as possible. Questionnaire design is generally undergraduate 10- 15 questions, and master students have one questionnaire. There are not many questions, so don't repeat them. You can subdivide them. The topic design is mostly single-choice questions, and multiple-choice questions are as few as possible, otherwise the paper analysis is not easy to write.

When the recovery rate of your questionnaire is higher than 75%, then your questionnaire can be used as the questionnaire analysis of graduation thesis. Not below 75%. General schools require a recovery rate of not less than 90%. That is, out of ten people, at least nine people filled out the questionnaire for you.

Data analysis software is usually spss. You can also use other slightly more complicated data analysis software according to your own papers and tutors.