I have done a questionnaire about the impact of social media on sales and I have got 91 responses out of 120 and I want to analyze it by using statistical data analysis to support my hypothesis.
What are your objectives? I believe your questionnaire items were designed based on your research objectives? Also, what are your variables (Independent variable and Dependent variable)? What is the level of measurement of your variables?
The easy way to start with applying statistical functions if applicable like mean, standard deviations, p-value, t-testing, or chi-square (if the data/outcomes are of numeric nature).
In your case, I believe chi-square test method may work to support your hypothesis.
It is difficult to say without knowing the type of data you collected (e.g., ordinal data, interval...) or how you formulated the measurement instrument. Since the sample size is small, you might not be able to do multivariate data analysis.
There are some answers to similar questions here at Researchgate which might be of interest to you. Have a look here: