The sample size should stay the same. There are times when you would throw out that person and draw another individual from the population. Since this is a first try at research, the student should draw no more than 20 to 25 respondents. Once the information is gathered, it is time to analyze the responses. Please see the chapters 14 and 15.
Students are to try and work out several mead, medians and modes for their research.
The text gives excellent examples of how to do this. Percentages are always good and helpful in this type of analysis as are use of charts and graphs. If using qualitative research, sharing the responses of the respondent is acceptable. You might indicate that, in the example of high school students, most students felt secure in their school environment, and then provide exact quotes from some of the students. Discussion of what each question indicated and sometimes combining questions is important.