Use the Given Degree of Confidence and Sample Data to Find

question 156

Multiple Choice

Use the given degree of confidence and sample data to find a confidence interval for the population standard deviation σ.
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 10.9 years and the standard deviation is 2.7 years. Construct a 99% confidence interval for the standard deviation, σ, of the replacement Times of all washing machines of this type.

• A) \(1.9 \mathrm { yr } < \sigma < 5.7 \mathrm { yr }\)
• B) \(1.8 \mathrm { yr } < \sigma < 5.1 \mathrm { yr }\)
• C) \(2.0 \mathrm { yr } < \sigma < 4.3 \mathrm { yr }\)
• D) \(1.9 \mathrm { yr } < \sigma < 4.5 \mathrm { yr }\)

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Definitions:

CNS

Central Nervous System, comprising the brain and spinal cord, responsible for integrating sensory information and responding accordingly.

Blood-Brain Barrier

A semi-permeable barrier of endothelial cells that prevents most substances in the blood from entering the brain, thereby maintaining the brain's chemical environment.

Toxic Substances

Materials or compounds that can cause harm to living organisms through ingestion, inhalation, or skin absorption.

Neurons

Specialized cells of the nervous system that transmit information through electrical and chemical signals.