The mean gross annual income of certified nurses are normally distributed with the mean of $\$50,000$ and a standard deviation of $\$6,000$. The nurse association wishes to find out whether their nurses earn more or less than $\$50,000$ annually.
A random sample of $400$ certified nurses was surveyed. The sample mean of these nurses' annual income is $\$56,000$ with a standard deviation of $\$7,000$.
Which of the following is the alternative hypothesis?