Life Tests Performed on a Sample of 13 Batteries of a New

question 83

Multiple Choice

Life tests performed on a sample of 13 batteries of a new model indicated: (1) an average life of 75 months, and (2) a standard deviation of 5 months.Other battery models, produced by similar processes, have normally distributed life spans.The 90% confidence interval for the population mean life of the new model is _________.

• A)66.78 to 83.23
• B)72.72 to 77.28
• C)72.53 to 77.47
• D)66.09 to 83.91
• E)73.34 to 76.25

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Definitions:

Factor Model

A way of decomposing the factors that influence a security’s rate of return into common (systematic) and firm-specific influences.

Firm-specific Events

Events that directly affect a company's operations, financial performance, or stock price, independent of the market or economic conditions.

Macroeconomic Events

Large-scale economic events that affect the economy on a national or global level, such as inflation, unemployment, or fiscal policies.

Unsystematic Risk

The segment of risk that is unique to a specific company or industry, also known as diversifiable risk, which can be mitigated through diversification.