SOLUTION: Lifetimes of AAA batteries are approximately normally distributed. A manufacturer wants to estimate the standard deviation of the lifetime of the AAA batteries it produces. A rando

Algebra ->  Statistics  -> Confidence-intervals -> SOLUTION: Lifetimes of AAA batteries are approximately normally distributed. A manufacturer wants to estimate the standard deviation of the lifetime of the AAA batteries it produces. A rando      Log On


   



Question 1080028: Lifetimes of AAA batteries are approximately normally distributed. A manufacturer wants to estimate the standard deviation of the lifetime of the AAA batteries it produces. A random sample of
22
AAA batteries produced by this manufacturer lasted a mean of
10.1
hours with a standard deviation of
1.9
hours. Find a
90%
confidence interval for the population standard deviation of the lifetimes of AAA batteries produced by the manufacturer. Then complete the table below.
Carry your intermediate computations to at least three decimal places. Round your answers to at least two decimal places.

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
90% CI here is mean +/- 1.721*s/sqrt(n)=1.721*1.9/sqrt (22)=0.6971
10.1+/-0.70
(9.40, 10.80)