U.S. politics
The national elections in 2008 appar- ently drew more interest and debate among voters than prior U.S. elections. A national sample of 2020 U.S. adults, aged 18 and older, surveyed over the telephone (using both landlines and cell phones) between January 30 and February 2 in 2008 by Gallup revealed that 71% reported that they had given "quite a lot" of thought to the upcoming election for president. Is there any evidence that the percentage has changed from the historically reported benchmark of 58% during the same timeframe in 2004?
a) Find the z-score of the observed proportion.
b) Compare the z-score to the critical value for a 0.1% significance level using a two-sided alternative.
c) Explain your conclusion.