What is the answer and what would the null hypothesis be

The director of philanthropy at the Fleckman Institute of the Arts is interested in assessing the impact that recent changes in federal tax laws have had on dona- tions. The average donor gave $580 last year. A random sample of 50 donations reveals that in the 5 months since the laws were changed, the average donor gave $625, with a standard deviation of $97. Present a hypothesis and a null hypoth- esis, and evaluate them. What can the director conclude about the effect the new tax laws are having on donations