In January 2016, at the end of his time in office, President Obama’s approval rating stood at 57% in Gallup’s daily tracking poll of 1500 randomly surveyed U.S. adults. (www.gallup.com/poll/113980/gallup-daily-obamajob-approval.aspx)
a) Make a 95% confidence interval for his approval rating by all U.S. adults.
b) Based on the confidence interval, test the null hypothesis that Obama’s approval rating was essentially the same as his approval rating of 52% when he was elected to his second term.