Question

Firebrick Tire Company wants to increase sales of its long running, low end Roadmaster Tire brand with a new advertising campaign claiming they will last at least 28,000 miles [u=28,000 miles]. Tests with a random sample [n=30 tires] show a sample mean [x=$27,500 miles] with a sample standard deviation [s=1000 miles]. At a .05 level of significance, these tests indicate

a. Reject Ho: Z of -2.7386 less than -1.6450
b. Reject Ho: Z of -2.7386 less than 1.6450
c. Do not reject Ho: Z of 1.6450 less than 2.7386
d. Do not reject Ho: Z of -1.6450 less than 2.7386
e. None of the Above