Final answer:
Inferential statistics are used by psychologists to determine whether an independent variable has had an effect by making inferences about the larger population from a sample and testing hypotheses.
Step-by-step explanation:
A psychologist who wants to use statistics to determine whether the independent variable has had an effect will typically use inferential statistics. Inferential statistics involve using a sample to make inferences about the larger population. This includes testing hypotheses to determine how likely it is that the observed effects are due to the independent variable rather than chance. In this context, using a t-test to compare means or other similar statistical tests would be examples of inferential statistics at work.