A 2018 Gallup poll of 3635 randomly selected Facebook users found that 2472 get most of their news about world events on Facebook. Research done in 2013 found that only 47% of all Facebook users reported getting their news about world events on Facebook. See page 430 for guidance.

a. Does this sample give evidence that the proportion of Facebook users who get their world news on Facebook has changed since 2013? Carry out a hypothesis test and use a 0.05 significance level.

b. After conducting the hypothesis test, a further question one might ask is what proportion of all Facebook users got most of their news about world events on Faceboo in 2018. Use the sample data to construct a 90% confidence interval for the population proportion. How does your confidence interval support your hypothesis test conclusion?