67. U.S. politics. The national elections in 2008 apparently 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.