The Quality Control Manager of a Major Cell Phone Provider $\alpha$

question 23

Multiple Choice

The quality control manager of a major cell phone provider is concerned about the life of the cell phone batteries they use.He took a sample of 13 batteries from a recent shipment and used them continuously until they failed to work.The manager measured the number of hours the batteries lasted and found the mean to be 550.4 with a standard deviation of 315.3.What is the critical value for $\alpha$ = .10 to test the claim that the mean life of the batteries is more than 400 hours.

• A)-1.356
• B)1.356
• C)1.282
• D)1.782
• E)-1.782

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Definitions:

Subsurface Mining

A method of extracting minerals and ores from beneath the earth's surface, as opposed to open-pit or surface mining, often requiring tunnels or shafts.

Disease

A disorder of structure or function in a living organism that typically leads to signs or symptoms and is not a direct result of physical injury.

Groundwater Supplies

Underground sources of fresh water stored in aquifers, crucial for drinking water, irrigation, and industrial uses.

Sulphur Content

The quantity of sulfur present in a material, which is significant in assessing air pollution potential, especially in fuels.