A company selling licenses for new e-commerce computer software advertises that firms using this software obtain, on average during the first year, a yield of 10% on their initial investments. A random sample of 10 of these franchises produced the following yields for the first year of operation:
6.1 9.2 11.5 8.6 12.1 3.9 8.4 10.1 9.4 8.9
Assuming that population yields are normally distributed, test the company's claim.