Question: The level of sulfur in batches of an aircraft fuel is claimed by the

manufacturer to be symmetrically distributed with a median value of 0.10%.

Successive batches are found to have sulphur concentrations of 0.09, 0.12, 0.10, 0.11,

0.08, 0.17, 0.12, 0.14, and 0.11%. Use the sign test, and the signed rank test to

check the manufacturer’s claim.