Answer:
The 90% confidence interval for p is (0.8236, 0.9564). The upper confidence limit for p is 0.9564.
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 .
He discovers that a particular weed killer is effective 89% of the time. Suppose that this estimate was based on a random sample of 60 applications.
This means that
90% 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:
The 90% confidence interval for p is (0.8236, 0.9564). The upper confidence limit for p is 0.9564.
