DDT is a pesticide banned in the United States for its danger to humans and animals. In an experiment on the impact of DDT, 6 rats were exposed to DDT poisoning and 6 rats were not. For each rat in the experiment, a measurement of nerve sensitivity was recorded. The researchers suspected that the mean nerve sensitivity for rats exposed to DDT is greater than that for rats not poisoned. The data follow:

Poisoned rats:	12.207	16.869	25.050	22.429	8.456	20.589
Unpoisoned rats:	11.074	9.686	12.064	9.351	8.182	6.642

Let _DDT be the mean nerve sensitivity for rats poisoned with DDT. Let _NE be the mean nerve sensitivity for rats not poisoned with DDT.

Which of the following is the alternative hypothesis for the relevant significance testing problem?

Select one:

a.

• H_0:_DDT =_NE
• H_a: _DDT> _NE

b.

• H_0:_DDT=_NE
• H_a: _DDT<_NE

c.

• H_0: _DDT = _NE
• H_a: _DDTNE