Question

You have to choose a battery brand to use in your smoke alarm. Company A's batteries have a mean lifespan of 1.2 years, with a standard deviation of 0.1 years. Company B's batteries have a mean lifespan of 1.5 years, with a standard deviation of 0.9 years. Which brand would you choose, and why?

Answer 1

Assuming a normal distribution:

95% A = 1.2 ± 2 * .1

95% B = 1.5 ± 2 * .9