Answer:
The 95% confidence interval for the proportion of cans in the shipment that meet the specification is (0.741, 0.917).
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:
70 cans, 58 meet the specification for puncture resistance. 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:
The 95% confidence interval for the proportion of cans in the shipment that meet the specification is (0.741, 0.917).