Questions: A vending machine dispenses coffee into a sixteen-ounce cup. The amount of coffee dispensed into the cup is normally distributed with a standard deviation of 0.03 ounce. You can allow the cup to overfill 2% of the time. What amount should you set as the mean amount of coffee to be dispensed?
ounces (Round to two decimal places as needed.)
Transcript text: A vending machine dispenses coffee into a sixteen-ounce cup. The amount of coffee dispensed into the cup is normally distributed with a standard deviation of 0.03 ounce. You can allow the cup to overfill $2 \%$ of the time. What amount should you set as the mean amount of coffee to be dispensed?
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$\square$ ounces
(Round to two decimal places as needed.)
Solution
Solution Steps
Step 1: Identify the Problem
We need to determine the mean amount of coffee to be dispensed into a 16-ounce cup such that the cup overfills only \(2\%\) of the time. The coffee amount is normally distributed with a standard deviation of \(0.03\) ounces.
Step 2: Determine the Z-score
To find the mean, we first need the Z-score corresponding to the \(98\%\) percentile (since \(2\%\) overfill is allowed). The Z-score for the \(98\%\) percentile is approximately \(2.0537\).
Step 3: Calculate the Mean Amount
Using the Z-score formula for a normal distribution:
\[
\text{mean} = \text{cup capacity} - (Z \times \text{standard deviation})
\]
Substitute the known values:
\[
\text{mean} = 16 - (2.0537 \times 0.03)
\]
\[
\text{mean} \approx 16 - 0.0616 = 15.9384
\]
Step 4: Round the Mean Amount
Round the mean amount to two decimal places:
\[
\text{mean} \approx 15.94
\]
Final Answer
The mean amount of coffee to be dispensed should be set to \(\boxed{15.94}\) ounces.