A 2011 NBC News survey found that 80% of a sample of 4500 American teens said they owned an MP3 player such as an iPod. Assume that the sample was an SRS. Suppose we computed a large sample 80% confidence interval for the proportion of all American teens who own an MP3 player. This 80% confidence interval. a) would have a smaller margin of error than the 90% confidence interval.
b) could have either a smaller or a larger margin of error than the 90% confidence interval. This varies from sample to sample.
c) would have a larger margin of error than the 90% confidence interval.