A study done on a marriage counseling course showed that the proportion of couples for which the communication program can prevent divorce is $78\mathrm{\%}$. Suppose we have strong reason to believe the proportion is less than $78\mathrm{\%}$, and we carry out a hypothesis test. State the null hypothesis ${\mathrm{H}}_0$ and the alternative hypothesis $H_1$ that we would use for this test.
$$\begin{array}{l}{H}_0:◻\\ H_1:◻\end{array}$$

Step 1 ：State the null hypothesis $H_0$ and the alternative hypothesis $H_1$ for the test.

Step 2 ：The null hypothesis $H_0$ is a statement of no effect or no difference. In this case, it would be that the proportion of couples for which the communication program can prevent divorce is $78\mathrm{\%}$.

Step 3 ：The alternative hypothesis $H_1$ is what we are testing against the null hypothesis. In this case, it would be that the proportion is less than $78\mathrm{\%}$.

Step 4 ：$$\begin{array}{l}{H}_0:\text{The proportion of couples for which the communication program can prevent divorce is }78\mathrm{\%}{\text{H}}_1:\text{The proportion of couples for which the communication program can prevent divorce is less than }78\mathrm{\%}\end{array}$$