State the null hypothesis, Ho, and the alternative hypothesis, Ha, that would be used to test these

Question:

State the null hypothesis, Ho, and the alternative hypothesis, Ha, that would be used to test these claims:
a. The variance has decreased from 34.5.
b. The standard deviation of shoe size is more than 0.32.
c. The standard deviation is at least 5.5.
d. The variance is at most 35.
e. The variance has shrunk from the value of 0.34 since the assembly lines were retooled.