In: Statistics and Probability
1. The Gallup organization periodically polls adults living in the U.S. about their approval or disapproval of the job the President of the U.S. is doing. At the end of President Trump’s first month in office, January 2017, his approval rating was 45%, while at the end of last month, March, 2020, his approval rating was 49%. For the purpose of this problem, suppose that the sample size was 200 in both months, that each represented a simple random sample of adults living in the U.S. at that time, and that the two samples were chosen independently of each other. Is there evidence for a real change in opinion among U.S. adults, or could this result be due just to chance?
(a) State the null hypothesis and alternative hypothesis in terms of the original problem.
Null: __________________________________________________________________________
Alternative: ____________________________________________________________________
(b) Under the null hypothesis, the difference in the percentages is expected to be ________%. The estimated standard error for this difference is ________%. (c) The two-sample z test statistic is __________.
(d) The p-value = _________%.
(e) Our conclusion is (circle one) reject the null hypothesis OR don’t reject the null hypothesis.