The 2017 Chapman University Survey of American Fears asked a random sample of 1207 adults Americans if they believed that aliens had come to Earth in modern times, and 26% responded yes.

a. What is the standard error for this estimate of the percentage of all Americans who believe that aliens have come to Earth in modern times?

b. Find a 95% confidence interval for the proportion of all Americans who believe that aliens have come to Earth in modern times.

c. What is the margin of error for the 95% confidence interval?

d. A similar poll conducted in 2016 found that 24.7% of Americans believed aliens have come to Earth in modern times. Based on your confidence interval, can you conclude that the proportion of Americans who believe this has increased since 2016?