Answer:
The appropriate null hypothesis is
![H_0: \mu = 1250](https://img.qammunity.org/2022/formulas/mathematics/high-school/clyfcmyrm746s2wz055rlxqk9yqoifuqyg.png)
The appropriate alternate hypothesis is
![H_a: \mu < 1250](https://img.qammunity.org/2022/formulas/mathematics/high-school/aje96o6zebvyhns0iezqc847r074nzlbgy.png)
Explanation:
At the null hypothesis, we test if the mean area is the advertised area of 1250 square feet, that is:
![H_0: \mu = 1250](https://img.qammunity.org/2022/formulas/mathematics/high-school/clyfcmyrm746s2wz055rlxqk9yqoifuqyg.png)
A tenant group thinks that the apartments are smaller than advertised.
Smaller, thus, at the alternate hypothesis, we test if the mean area is less than the advertised area of 1250 square feet, that is:
![H_a: \mu < 1250](https://img.qammunity.org/2022/formulas/mathematics/high-school/aje96o6zebvyhns0iezqc847r074nzlbgy.png)