Answer:
The null hypothesis is:

The alternative hypothesis is:

Explanation:
Consider the provided information.
It is given that the average air pressure in footballs used by the Patriots was significantly less than the allowable limit of 12.5 psi.
The null hypothesis indicates that there is no substantial difference between given populations, due to sampling or experimental error, any observed difference.
Therefore, the null hypothesis is:

The required alternative hypothesis is:
