THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
The number of beverage cans produced each hour from a vending machine is normally distributed with a standard deviation of 8.6.For a random sample of 12 hours,the average number of beverage cans produced was 326.0.Assume a 99% confidence interval for the population mean number of beverage cans produced per hour.
-Calculate the width of the 99% confidence interval estimate.
A)12.81
B)3.21
C)6.41
D)7.20

Question

Quizplus · Accepted Answer

The width of the confidence interval is calculated using the formula: $W = 2 \times (Z \times \frac{\sigma}{\sqrt{n}})$, where $Z$ is the Z-value corresponding to the confidence level (for 99%, $Z \approx 2.576$), $\sigma$ is the standard deviation (8.6), and $n$ is the sample size (12). Plugging in the values: $W = 2 \times (2.576 \times \frac{8.6}{\sqrt{12}}) \approx 12.81$.