Use the Given Degree of Confidence and Sample Data to Find

question 37

Multiple Choice

Use the given degree of confidence and sample data to find a confidence interval for the population standard deviation ?.
Assume that the population has a normal distribution. Round the confidence interval limits to the same number of decimal places as the sample standard deviation.
-The mean replacement time for a random sample of 20 washing machines is 9.4 years and the standard deviation is 2.5 years. Construct a 99% confidence interval for the standard deviation, ?, of the replacement times of all washing machines of this type.

• A) \(1.8 \mathrm { yr } < \sigma < 4.2 \mathrm { yr }\)
• B) \(1.8 \mathrm { yr } < \sigma < 3.9 \mathrm { yr }\)
• C) \(1.7 \mathrm { yr } < \sigma < 4.8 \mathrm { yr }\)
• D) \(1.8 \mathrm { yr } < \sigma < 5.3 \mathrm { yr }\)

---

Definitions:

Return On Investment

A metric for determining an investment's profitability or efficiency, achieved by dividing the net profit by the investment's total cost.

Invested Assets

Resources or funds committed to ventures with the expectation of generating income or profit.

Investment Center

A business segment or unit within an organization that is responsible for its own revenues, expenses, and investments.

Department Manager

An individual responsible for overseeing the operations, budget, and personnel of a specific department within a company.