i think this question calls for a confidence interval calculation but im not sure. what formula do i use and how do i go about using it. using calculators i came up with an interval of 3.1. is this right?
Jones and Smith are currently locked in an intense race for Congress. A local talking head recently claimed that 55% of the likely voters support Jones while only 45% support Smith. In order to test that proposition, you commission a poll that randomly sampled 1000 likely voters. In reviewing the results of the poll, you observe that the sampled population proportion was actually only 51.5% for Jones. Assuming that the sampling was correctly obtained and that voter preferences are stable over the period in question, is there suficient evidence to conclude that the population proportion differs from the 55% that expert claimed?