Test Hypotheses About a Population Mean with Unknown
-A Manufacturer $\alpha = 0.05$

Short Answer

Test Hypotheses about a Population Mean with Unknown
-A manufacturer claims that the mean lifetime of its lithium batteries is 1000 hours. A homeowner selects 25 of these batteries and finds the mean lifetime to be 990 hours with a standard deviation of 80 hours. Test the manufacturer's claim. Use $\alpha = 0.05$ .