The 99 percent confidence interval for the true mean length of the bolt is CI = (2.8712, 3.1288)
<h3>How to find the confidence interval?</h3>
Confidence Interval is used to tell us the degree of certainty or uncertainty that is existent in a sampling method.
The general formula for confidence interval is;
CI = x' ± z(s/√n)
where;
x' is sample mean
z is z-score at confidence level
s is sample standard deviation
n is sample size
We are given;
sample size; n = 36
Sample mean; x' = 3 inches
standard deviation; s = 0.3 inches
confidence level = 99%
z at 99% CL = 2.576
Thus;
CI = 3 ± 2.576(0.3/√36)
CI = 3 ± 0.1288
CI = (2.8712, 3.1288)
Read more about Confidence Interval at; brainly.com/question/17097944
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