If we randomly select groups of 25 batteries, measure how many hours they last, and then take the average of the 25 lifetimes, we find that the average lifetimes are normally distributed. (a) We get a group of 25 batteries and find that their average lifetime is 109 hours with a standard deviation of 18 hours. What is the probability that we would get a group of 25 batteries with an average lifetime of 109 hours or more if the average lifetime of all batteries is 97 hours? (b) We get a group of 25 batteries and find that their average lifetime is 93 hours with a standard deviation of 18 hours. What is the probability that we would get a group of 25 batteries with an average lifetime of 93 hours or less if the average lifetime of all batteries is 97 hours? Is this probability significant at the 0.05 level? (one-tailed) (c) We get a group of 25 batteries and find that their average lifetime is 109 hours with a standard deviation of 18 hours. Based on this data, we can say with 95% confidence that the average lifetime of all batteries is between ______ & ______
If we randomly select groups of 25 batteries, measure how many hours they last, and then take the average of the 25 lifetimes, we find that the average lifetimes are normally distributed.
(a) We get a group of 25 batteries and find that their average lifetime is 109 hours with a standard deviation of 18 hours. What is the
(b) We get a group of 25 batteries and find that their average lifetime is 93 hours with a standard deviation of 18 hours. What is the probability that we would get a group of 25 batteries with an average lifetime of 93 hours or less if the average lifetime of all batteries is 97 hours?
Is this probability significant at the 0.05 level? (one-tailed)
(c) We get a group of 25 batteries and find that their average lifetime is 109 hours with a standard deviation of 18 hours. Based on this data, we can say with 95% confidence that the average lifetime of all batteries is between ______ & ______
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