A pre-election survey estimates that a candidate will get 42% of the votes, with a margin of error of 3% at a confidence level of 95%. The survey means that we are 95% confident that the candidate will get
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → between 39% and 45% of the votes
A confidence interval is the estimate minus the margin of error to the estimate plus the margin of error:
Lower limit = 42% − 3% = 39%
Upper limit = 42% + 3% = 45%
So we are 95% confident that the candidate’s share of the votes will be between 39% and 45%.