1. 800 people took part to a market research. 40,8 % of those people said that they accept that there comes a new nuclear power plant to their country.

What is the percentage of people who accept this nuclear power plant with 95 % confidence interval?

2. 856 people took part to a market research. People were asked about their political orientation. They were given numbers from 1 to 10 and they could choose where they think they are politically, when small numbers tell that they are on "left-wing" and big numbers tell that they are on "right-wing".

Average of answers was 5,61 and standard deviation 1,92.

What is the expected value of answers with 95 % confidence interval?

3. Students were asked how much money they use to groceries in a month.

273 students answered to this question. Average amount was 188,02 euros and standard deviation was 155,09 euros.

What is the expected value of answers with 95 % confidence interval?

4. 277 students answered to a research. 55,2 % of those said that they are working beside studies.

What is the percentage of students that have a job with 95 % confidence interval?