A Gallup Poll reported the percentage of Americans who approve of the President's job performance was 47% with a margin of error of 2 percentage points. What is a 95% confidence interval for the population percentage?
A. 41% to 53%
B. 45% to 49%
C. 46% to 48%
D. 43% to 51%
Calculate .47 ± .02 for your interval. Convert to a percent to make your selection.
To calculate the confidence interval, we need to consider the margin of error and the desired confidence level. In this case, the margin of error is 2 percentage points and the desired confidence level is 95%.
To find the confidence interval, we can subtract the margin of error from the sample percentage to get the lower bound, and add the margin of error to the sample percentage to get the upper bound. In this case, the sample percentage is 47%, so:
Lower bound = 47% - 2% = 45%
Upper bound = 47% + 2% = 49%
Therefore, the 95% confidence interval for the population percentage is:
B. 45% to 49%