When testing a hypothesis using a null hypothesis, you use a statement that negates your hypothesis, and, within a certain level of certainty, see if the null hypothesis can be rejected. When testing the null hypothesis, you typically want to be around 95% sure that you can reject it (confidence interval is 95%).
In Rose's case, she is testing the hypothesis that there is a correlation between watching violence on television and aggressive behavior.
Her null hypothesis would be:
"There is not a positive correlation between watching violence on television and aggressive behavior"
or
"The correlation between watching violence on television and aggressive behavior is less than or equal to zero"
Depends on what you think...
if you think rewards make people more likely to follow the norms of society then it could be because they get something out of it and it is some sort of bribery or motivation,
if you think punishments make people more likely to follow the norms of society, it could be because they don't want the punishment and it is threatening.
When a place limits their production to one or a few goods and services