Question

A poll asked the question, “What do you think is the most important problem facing this country today?” Twenty one percent of the respondents answered “crime and violence”. The margin of sampling error was plus or minis 2 percentahe points. Following the convention that the margin of error is based on a 95% interval, find a 95% confidence interval for the percentage of the population that would respond “crime and violence” to the question asked by the pollsters.

lower limit-

upper limit-

Answer 1

Here,

Point estimate = 21%

Margin of error = +/- 2%

95% confidence interval for percent of population responders that would respond 'Crime and violence' to the question asked

lower limit = point estimate - margin of error

lower limit = 21% - 2%

lower limit = 19%

upper limit = point estimate + margin of error

upper limit = 21% + 2%

upper limit = 23%