Answer:
it is correct to conclude that rats prefer food A over food B
the standard deviation is zero
Step-by-step explanation:
In the experiment performed when both meals are available, rats prefer food A and eat only B when no other is available.
Therefore it is correct to conclude that rats prefer food A over food B
This conclusion is correct because ours is significant with a population of 50 animals all have the same preference for which the standard deviation is zero