Julie is a scientist and she is doing an experiment on guinea pigs. she feeds one group of guinea pigs grapes and the other group strawberries.

she injects both groups of mice with the flu virus. the mice that ate the grapes did not get the flu, but many of the mice with the strawberry diet became sick with the flu.

julie concludes that people who eat grapes will not get the flu when exposed to the virus.
problem:
is julie's conclusion valid?
no, julie didn't test the grape diet on humans.
yes, the experiment showed that eating strawberries will not protect you from the flu.
no, the grape diet didn't adequately prove it could protect against the flu virus.
yes, the experiment showed the grape diet did protect the guinea from the flu