Suppose the Life of a Particular Brand of Calculator Battery

question 47

Multiple Choice

Suppose the life of a particular brand of calculator battery is approximately normally distributed with a mean of 75 hours and a standard deviation of 10 hours. If the manufacturer of the battery is able to reduce the standard deviation of battery life from 10 to 9 hours, what would be the probability that 16 batteries randomly sampled from the population will have a sample mean life of between 70 and 80 hours?

• A) 0.6127
• B) 0.8124
• C) 0.9736
• D) 0.8812

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Definitions:

Secondary Sex Characteristics

Changes that develop during puberty; in males, include growth of facial and body hair, muscle development, and the increase in vocal cord length and thickness that causes the voice to deepen; in females, include development of the breasts, broadening of the pelvis, and the development and distribution of muscle and fat responsible for the female body shape.

Testes

The male reproductive glands that produce sperm and hormones, such as testosterone.

Fight-or-Flight Response

An acute stress response involving physiological changes that prepare the body to either confront or flee from a threat.

Uterus

A major female reproductive organ where the development of the embryo and fetus occurs during pregnancy.