Answer:
a. [.243, .311]
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of , we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
For this problem, we have that:
In a randomly selected group of 650 automobile deaths, 180 were alcohol related. This means that
95% confidence level
So , z is the value of Z that has a pvalue of , so .
The lower limit of this interval is:
The upper limit of this interval is:
So the correct answer is:
a. [.243, .311]