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

question 12

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.Which most closely reflects the probability that a randomly selected bulb would last fewer than 1100 hours?

• A)0.4772
• B)0.9772
• C)0.0228
• D)0.5228
• E)0.5513

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Definitions:

Independent Events

Events whose occurrence or outcome does not influence the occurrence or outcome of another event.

Conditional Probability

The probability of an event occurring, given that another event has already occurred.

P(A|B)

The probability of event A occurring given that event B has already occurred.

Probability

A quantification of the probability that an event will happen, represented as a numerical value ranging from 0 to 1.