Given Exercise described an Experian/ Gallup poll of 1008 adults which found that 8% of them were worried about their ability to make their monthly payments. A more detailed poll surveyed 1288 adults, reporting similar overall results and also noting differences among four age groups: 18 - 29, 30 - 49, 50 - 64, and 65+.
a) Do you expect the 95% confidence interval for the true proportion of all 18- to 29-year-olds who are worried to be wider or narrower than the 95% confidence interval for the true proportion of all U.S. consumers? Explain.
b) Do you expect this second poll s overall margin of error to be larger or smaller than the Experian/Gallup poll s? Explain.
Exercise :
Payments. In a May 2007 Experian/Gallup Personal Credit Index poll of 1008 U.S. adults aged 18 and over, 8% of respondents said they were very uncomfortable with their ability to make their monthly payments on their current debt during the next three months. Find a 95% confidence interval for the proportion of the adult population that feels this way. Be sure to check the appropriate conditions and interpret your interval correctly.