A beverage dispensing machine is calibrated so that the amount of beverage dispensed is approximately normally distributed with a population standard deviation of 0.15 deciliters (dL). Compute a 95% confidence interval for the mean amount of beverage dispensed by this machine based on a random sample of 36 drinks dispensing an average of 2.25 dL. (State your answer as lower limit, upper limit).

Let's Do It! 10.17

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How large of a sample would you need if you want the width of the 95% confidence interval to be 0.04?
Would a 90% confidence interval be wider or narrower than the interval above.

Narrower
Wider