A company manufactures wind turbines. A random sample of 25 turbines is taken and the sample...
A company manufactures wind turbines. A random sample of 25 turbines is taken and the sample mean life is 20.00 years with a standard deviation of 2.50 years. If you were constructing a 95% two-sided confidence interval estimate, the upper limit would be:
Homework Answers
The upper limit is
Xbar + z×sigma/sqrt(n)
Where xbar is sample mean, sigma is standard deviation, z is 95% critical value and n is sample size.
Upper limit = 20 + (1.96×2.5 / sqrt(25))
= 20 + 0.98
= 20.98
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