Is the null hypothesis a statement about the value of a popu

Is the null hypothesis a statement about the value of a population parameter developed for the purpose of testing?

Solution

Not necessarily, but it happens. It happens when a previous data is known, and you want to test whether it still applies. It also happens when a value for the population parameter is claimed.

However, it is not always the case. For example, the null hypothesis can be about a distribution of data, or relationship between means of groups, or dependence between variables.