Question: As was described in Exercise, a July 2002 Gallup poll of n = 1004 randomly selected U.S. adults found that 55% felt that their weight was about right. In a similar poll in 1990, about 46% felt that their weight was about right. The margin of error for each poll was 3%.
a. Based on these results, is it reasonable to conclude that the population proportions thinking their weight is about right were different in 1990 and 2002?
b. Assuming that the sample size was 1004 in the 1990 poll as well, find a 95% confidence interval for the difference in the population proportions.
c. On the basis of the interval that you found in part (b), formulate a conclusion about whether the population proportion was different in 2002 than it was in 1990. Write your conclusion in words that would be understood by someone with no training in statistics.
Exercise: A Gallup Organization poll of n = 1004 randomly selected American adults in July 2002 found that 55% of those surveyed felt that their weight was about right. The margin of error for the survey was given as 3% (Source: https://www .gallup.com).
a. Find a 95% confidence interval estimate of the percentage of American adults who think their weight is about right.
b. Based on the interval computed in part (a), explain whether it is reasonable to say that more than 50% of American adults think their weight is about right.