In a random sample of 20 customers at a local fast-food restaurant, the mean waiting time to order is 95 seconds, and the standard deviation is 21 seconds. Assume the waiting times are normally distributed and construct a 99% confidence interval for the mean wait time of all customers.
Added by David A.
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861 \times \frac{21}{\sqrt{20}} \] \[ \text{Margin of Error} = 2.861 \times \frac{21}{4.47} \] \[ \text{Margin of Error} = 2.861 \times 4.70 \] \[ \text{Margin of Error} = 13.43 \] ** Show more…
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