The Expected (Mean)life of a Particular Type of Light Bulb

question 10

Multiple Choice

The expected (mean) life of a particular type of light bulb is 1,000 hours with a standard deviation of 50 hours. The life of this bulb is normally distributed. What is the probability that a randomly selected bulb would last longer than 1150 hours?

• A) 0.4987
• B) 0.9987
• C) 0.0013
• D) 0.5013
• E) 0.5513

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Definitions:

Linear Equations

Equations of the first degree, meaning they involve only first-degree variables and constants, typically having a straight line as their graph.

Method Of Elimination

A technique used in solving systems of equations where one variable is eliminated by adding or subtracting the equations in order to solve for the other variable.

Fractions

A way of representing parts of a whole or a division of quantities.

Linear Equations

Equations that graph as straight lines and can be written in the form Ax + By = C, where A, B, and C are constants.