Brian Vanecek, VP of Operations at Portland Trust Bank, Is

question 21

Multiple Choice

Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers.Brian would like to minimize the variance of waiting time for these customers, since this would mean each customer received the same level of service.Accordingly, his staff recorded the waiting times for 15 randomly selected walk-in customers, and determined that their mean waiting time was 15 minutes and that the standard deviation was 4 minutes.Assume that waiting time is normally distributed.The 90% confidence interval for the population variance of waiting times is ________.

• A)9.46 to 34.09
• B)56.25 to 64.87
• C)11.05 to 16.03
• D)8.58 to 39.79
• E)12.50 to 42.35

---

Definitions:

Oxygen

A chemical element with symbol O and atomic number 8, essential for life as part of the process of respiration.

Electrons

Subatomic particles with a negative charge, orbiting the nucleus of an atom and involved in chemical bonds and electrical conductivity.

Oxidized

A chemical process where a substance loses electrons, often associated with the gain of oxygen or the loss of hydrogen.

Non-metal Free Elements

Elements that exist in their natural state not combined with other elements and do not display metallic characteristics; examples include oxygen (O2) and nitrogen (N2).