\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
A company manufactures batteries. The battery life is normally distributed with a standard deviation \(\sigma = 12\) minutes. A random sample of 36 batteries is tested, yielding a mean life of \(240\) minutes.
Find the \(99\pourcent\) confidence interval for the true mean battery life \(\mu\).
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