Answer: lower bound = 0.7404; upper bound = 0.8596
Step-by-step explanation:
The proportion p for this population:
p = [tex]\frac{240}{300}[/tex]
p = 0.8
Confidence interval for proportion is calculated as:
p ± z-score.[tex]\sqrt{\frac{p(1-p)}{n} }[/tex]
Z-score for a 99% confidence interval is: z = 2.58
Calculating:
0.8 ± 2.58.[tex]\sqrt{\frac{0.8(0.2)}{300} }[/tex]
0.8 ± 2.58.[tex]\sqrt{0.00053}[/tex]
0.8 ± 2.58(0.0231)
0.8 ± 0.0596
This means that the lower limit of this interval is 0.7404 and upper bound is 0.8596
