Answer:
The following hypotheses is a null hypothesis:
There is no difference in the monthly grocery bills of families with one child and families with two children.
Step-by-step explanation:
In inferential statistics, it is a null hypothesis because it is assuming to be true until evidence indicates otherwise, it is a general position without relationship between the two measured phenomena (one child and two children), testing (accepting, approving, rejecting, or disproving), concluding that there are not reasons for believing that there is a relationship between two phenomena and gives precise criteria for rejecting the null hypothesis within a confidence level.