A manufacturer claims that the mean lifetime of its drill is 1000 hours. A homeowner selects 25 drills and finds the mean lifetime to be 980 hours with a sample standard deviation of 80 hours. If = 0.05, test the manufacturer's claim.

Divide. write in the simplest form. 4 1/6 divided by 10

Acollection of coins has value of 64 cents. there are two more nickels than dimes and three times as many pennies as dimes in this collection. how many of each kind of coin are in the collection?

Suppose that 3% of all athletes are using the endurance-enhancing hormone epo (you should be able to simply compute the percentage of all athletes that are not using epo). for our purposes, a “positive” test result is one that indicates presence of epo in an athlete’s bloodstream. the probability of a positive result, given the presence of epo is .99. the probability of a negative result, when epo is not present, is .90. what is the probability that a randomly selected athlete tests positive for epo? 0.0297