Two companies make batteries for cell phone manufacturers, One company claims a

Question

Two companies make batteries for cell phone manufacturers, One company claims a mean life span of 2.5 years, while the other company claims a mean life span of 3 years (assuming average use of minutes/month for the cell phone). a) Explain why you would also like to know the standard deviations of the battery life spans before deciding which brand to buy. b) Suppose those standard deviations are 1.5 months for the first company and 8 months for the second company. Does this change your opinion of the batteries? Explain. a) Choose the correct answer below. O A. To know about their consistency and how long they might last. A type of battery with a small standard deviation would be more likely to have life spans closer to their mean. O B. To know about their consistency and how long they might last. A type of battery with a large standard deviation would be more likely to have Ife spans closer to their mean. o c. To know about the accuracy of the mean. A battery with a large standard deviation has a true mean that is closer to the advertised mean. o D. To know about the accuracy of the mean. A type of battery with a small standard deviation has a true mean that is closer to the advertised moan. b) The second company's batteries have a mean life span and a V standard deviation. The decision is not clear-cut. The first company's batteries are V to fail in less than 25.5 months, but the second companys batteries V) ikely to fail in that time span. The second companies batteries V last longer than 34.5 months, a span very V for the first company.

Explanation / Answer

Answer:- a) The correct answer is D.i.eTo know about the accuracy of the mean. A type of battery with a small standard deviation has a true mean that is closer to the advertised mean.

B) The second company's batteries have a 3 year mean life span and a 8 month standard deviation. The decision is not clear-cut. The first company's batteries are. The first company's batteries are 23 month to fail in less than 25.5 month, but the second company's batteries 28 month likely to fail in that life span. The second company's batteries are 1.5 month last longer than 34.5 months, a span very 6 month for the first company.

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