Answer: (0.1118, 0.3454)
Step-by-step explanation:
Confidence interval for population proportion is given by :-
[tex]\hat{p}\pm z^c\sqrt{\dfrac{\hat{p}(1-\hat{p})}{n}}[/tex] , where [tex]\hat{p}[/tex]= sample proportion , n= sample size, [tex]z^c[/tex] = critical z-value for c confidence level.
Let p = the proportion of all households in Cherry Creek that pretend not to be home on Halloween.
Given : n= 35
[tex]\hat{p}=\dfrac{8}{35}\approx0.2286[/tex]
Critical z-value for 90% confidence level =1.645
A 90% confidence interval for p, the proportion of all households in Cherry Creek that pretend not to be home on Halloween:
[tex]0.2286\pm (1.645)\sqrt{\dfrac{0.2286(1-0.2286)}{35}}\\\\=0.2286\pm 0.1168\\\\=(0.2286-0.1168,\ 0.2286+0.1168)\\\\=(0.1118,\ 0.3454)[/tex]
∴ Required confidence interval : (0.1118, 0.3454)
