"True" Mean and Assurance Period. Probably the most often used illustrative figure is the mean. The mean is a particularly useful evaluate of the "central tendency" of the varying if it is revealed along with its confidence durations. As said before, usually we are enthusiastic about research (such as the mean) from our example only to the stage to which they can infer details about the inhabitants. The arrogance durations for the mean provide us with a variety of principles around the mean where we anticipate the "true" (population) mean is situated (with a given stage of confidence, see also Primary Concepts).