A ______ is a statement about an expected outcome or relationship involving population parameters.

A) null hypothesis
B) statistical hypothesis
C) sampling error
D) alternative hypothesis

A statistical hypothesis is a statement about the expected outcome or relationship between population parameters. The null hypothesis (A) is a specific type of statistical hypothesis that assumes there is no relationship between variables or no difference between groups. Sampling error (C) refers to the natural variation that occurs when taking a sample from a population. The alternative hypothesis (D) is a competing hypothesis to the null hypothesis and assumes that there is a relationship between variables or a difference between groups.