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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A congregation of organisms that resemble each other and can engage in gene exchange or reproduction.

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