Respuesta :
Answer:
[tex]0.81 - 2.326 \sqrt{\frac{0.81(1-0.81)}{131}}=0.730[/tex]
[tex]0.81 + 2.326 \sqrt{\frac{0.81(1-0.81)}{131}}=0.890[/tex]
And the confidence interval would be:
[tex] 0.730 \leq \p \leq 0.890[/tex]
Step-by-step explanation:
Information given:
[tex] n=131[/tex] represent the sample size
[tex] \hat p=0.81[/tex] represent the estimated proportion
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 98% confidence interval the value of [tex]\alpha=1-0.98=0.02[/tex] and [tex]\alpha/2=0.01[/tex], with that value we can find the quantile required for the interval in the normal standard distribution.
[tex]z_{\alpha/2}=2.326[/tex]
And replacing into the confidence interval formula we got:
[tex]0.81 - 2.326 \sqrt{\frac{0.81(1-0.81)}{131}}=0.730[/tex]
[tex]0.81 + 2.326 \sqrt{\frac{0.81(1-0.81)}{131}}=0.890[/tex]
And the confidence interval would be:
[tex] 0.730 \leq \p \leq 0.890[/tex]
