The Lifetime (In Hours)of a 60-Watt Light Bulb Is a Random

question 49

Multiple Choice

The lifetime (in hours) of a 60-watt light bulb is a random variable that has a Normal distribution with  = 30 hours.A random sample of 25 bulbs put on test produced a sample mean lifetime of = 1038.If in the study of the lifetime of 60-watt light bulbs it was desired to have a margin of error no larger than 6 hours with 99% confidence,how many randomly selected 60-watt light bulbs should be tested to achieve this result?

• A)13
• B)97
• C)165
• D)42
• E)Not within ± 2 of any of the above

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Definitions:

UV-B Radiation

A portion of the ultraviolet spectrum with wavelengths from 280 to 315 nanometers, known for its biological effects, including DNA damage and vitamin D synthesis in skin.

Acid Rain

Precipitation with a pH lower than normal, resulting from atmospheric pollution that causes environmental harm.

Adaptive Radiation

A process in which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches.

Tempo

The speed or pace at which something happens or evolves.