Respuesta :
Answer:
The 95% confidence interval would be given (0.419;0.481).
Step-by-step explanation:
Data given and notation
n=1000 represent the random sample taken
X=450 represent the people in the sample favored Candidate A
[tex]\hat p=\frac{450}{1000}=0.45[/tex] estimated proportion of people in the sample favored Candidate A
[tex]\alpha=0.05[/tex] represent the significance level
Confidence =0.95 or 95%
p= population proportion of people in the sample favored Candidate A
Solution to the problem
The confidence interval would be given by this formula
[tex]\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]
For the 95% confidence interval the value of [tex]\alpha=1-0.5=0.05[/tex] and [tex]\alpha/2=0.025[/tex], with that value we can find the quantile required for the interval in the normal standard distribution.
[tex]z_{\alpha/2}=1.96[/tex]
And replacing into the confidence interval formula we got:
[tex]0.45 - 1.96 \sqrt{\frac{0.45(1-0.45)}{1000}}=0.419[/tex]
[tex]0.45 + 1.96 \sqrt{\frac{0.45(1-0.45)}{1000}}=0.481[/tex]
And the 95% confidence interval would be given (0.419;0.481).
We are confident (95%) that about 41.9% to 48.1% of the people are favored Candidate A.
