a) We get a group of 18 batteries and find that their average lifetime is 107 hours with a standard deviation of 17 hours. What is the probability that we would get a group of 18 batteries with an...

a) We get a group of 18 batteries and find that their average lifetime is 107 hours with a standard deviation of 17 hours. What is the probability that we would get a group of 18 batteries with an average lifetime of 107 hours or more if the average lifetime of all batteries is 97 hours?

b) We get a group of 18 batteries and find that their average lifetime is 95 hours with a standard deviation of 17 hours. What is the probability that we would get a group of 18 batteries with an average lifetime of 95 hours or less if the average lifetime of all batteries is 97 hours?

C) We get a group of 18 batteries and find that their average lifetime is 107 hours with a standard deviation of 17 hours. Based on this data, we can say with 95% confidence that the average lifetime of all batteries is between