sampling probabitlity

[jessi]

400 students were surveyed one week prior to the election for student body president regarding their choice of three candidates. The table below shows the results of the survey

candidate A B C
votes 250 116 34

a) There are 2400 students in the school. According to the survey about how many votes can each candidate expect to receive?

b) Assume the survey has a 4% margin of error. Estimate an interval for the number of votes expected to go for Candidate A.

[JohnM]

a) the percentages of votes for each candidate in the sample of 400 are assumed to be the same as with the population of 2400

so, if candidate A received 250/400 in the sample, that's = 0.625, so we'd expect him to get 62.5% of the 2400 votes

follow the same logic with the other candidates

b) .625 +/- .04