Question: Abuse of substances containing toluene can produce various neurological symptoms. Researchers have measured the concentrations of various chemicals in the brains of rats that had been exposed to a toluene-laden atmosphere compared with the concentrations initially. The concentrations of the brain chemical norepinephrine (NE) in the medulla region of the brain, for six rats are shown below.

NE Concentration (ng/mg protein)

Toluene (final values) Control (initial values)

Determine whether there is a significant difference between the two states at p< 0.05.