All of the following refer to cell phones mean battery life of 12 hours and a standard deviation of 1 hour.

Your firm manufacturers cell phones and guarantees that the battery life is at least 9.5 hours long.What percentage of the time will your firm have to pay off on this guarantee because the battery life is less than 9.5 hours? answer 0.62% formula =NORM.DIST(9.5,12,1,TRUE)

Your firm offers a bonus of a free case to any cell phone user who can show that their battery life is longer than 13.5 hours. What percentage of the time will your firm have to give out a free case because the battery life is greater than 13.5 hours? answer 6.68% (((( what is formula))

Your firm wants to control the number of free cases they give out for customers who have a longer than average battery life.At what number should the number of hours for the bonus case be set so that the company only has to give a free case to 3% of customers?Format your answer with four digits after the decimal point. answer 13.8808 ((((what is formula))))

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