Scenario: It is a known medical fact that just slightly fewer females than males are born (although the reasons are not completely understood); the known "proper" baseline female birthrate is about 49% females.
In some cultures, male children are traditionally looked on more favorably than female children, and there is concern that the increasing availability of ultrasound may lead to pregnant mothers deciding to abort the fetus if it’s not the culturally "desired" gender. If this is happening, then the proportion of females in those nations would be significantly lower than the proper baseline rate.
To test whether the proportion of females born in India is lower than the proper baseline female birthrate, a study investigates a random sample of 6,500 births from hospital files in India, and finds 44.8% females born among the sample.
The null hypothesis in this case is: