The lives of many people are affected by a fear that prevents them from flying. An institute for public opinion conducted a poll of 1014 adults, 48%of whom were men. The results reported in USAToday showed 12 % of the men and 33% of the women fear flying.
1. Construct a 95% confidence interval estimate of the difference between the percentage of men and the percentage of women who fear flying. Do the confidence interval limits contain 0, and what is the significance of whether they do or do not?
2. In a separate Gallup poll , 1001 randomly selected adults were asked this questions: "If you had to fly on an airplane tomorrow, how would you describe your feelings about flying? Would you-be very afraid, somewhat afraid, not very afraid, or not afraid at all? "Here are the responses: very afraid (18%) somewhat afraid (26%), not very afraid, (17%), not afraid at all (38%) and no opinion (1%). Are these Gallup poll results consistent with those obtained by the survey conducted by the Marist Institute for The Public Opinion? Explain. Can discrepancies be explained by the fact that the Gallup survey was conducted after the terrorist attacks of September 11,2001,whereas the other survey conducted before the date?
Testing of proportion based on Z test.