Question

From an Angus Reid Public Opinion Poll. In which respondents were asked if they felt that U.S. nuclear weapons made them feel safer: n=1005 , x=543 who said "yes".

A) Using Technology* Construct a 95% confidence interval for the population proportion p. Round the lower and upper confidence interval limits for 4 decimal places.

-Which technology did you use to find your answer? Description of the steps or screenshot provided.

B) Interperet your confidence interval.

Answer 1

A) = 543/1005 = 0.5403

At 95% confidence level, the critical value is z_0.025 = 1.96

The 95% confidence interval is

+/- z_0.025 * sqrt((1 - )/n)

= 0.5403 +/- 1.96 * sqrt(0.5403(1 - 0.5403)/1005)

= 0.5403 +/- 0.0308

= 0.5095, 0.5711

B) We are 95% confident that the true population proportion of respondents who felt that U.S. nuclear weapons made them feel safer lies within the confidence limits 0.5095 and 0.5711.