1. What is the difference between one-sample t-test and 2-sample t-test? give some concrete examples

2. What are the common mistakes in survey design? How can we avoid those mistakes? Please give concrete examples.

3. It is a common practice for survey designers to include "neutral" in the scale. For example,

Do you agree that Obama care is a good policy? Rate this statement using a 5-point Likert scale:

1= strong disagree 2 = disagree 3=neutral 4=agree 5=strongly agree

•Peter, Paul, and Mary chose "3".
•Peter's position: "I am not sure. There are both pros and cons in this policy."
•Paul's position: "I already have my own insurance. I don't care."
•Mary's position: "I am a new immigrant. I don't know what Obamacare is. No idea!"

Are these "neutral" answers the same? If not, what number(s) should you assign to their positions? How would you rewrite the options (If necessary)?