Friendly Neighbors
A September 2015 Pew Research Center survey showed that 71% of the randomly selected people living in Asia-Pacific view Japan as a favorable neighbor. (This was up from 68% in October 2014.)
Suppose the margin of error was 2 percentage points with a 95% confidence interval. Assume that the conditions hold for all parts.
a. Report the confidence interval for the population percentage that held Japan as a favorable neighbor in 2015 using a carefully worded sentence.
b. If the sample size were larger and sample proportions stayed the same, would the interval be wider or narrower than the one obtained in part a.
c. If the confidence level were 99% and nothing else changed, would the interval be narrower or wider than the one obtained in part a.
d. The total population of adults in Asia-Pacific is 36.84 billion. Suppose the population had been one-third of that. Would that have changed any of your answers?